As Fat Bear Junior (September 23 – 24) and Fat Bear Week (September 29 – October 5) approach, it’s still prime time on the explore.org bearcams in Katmai National Park, Alaska. To discuss bears, salmon, and my book—The Bears of Brooks Falls—I’ll be joining Paulina Springs Books in Sisters, Oregon today at 9:30 p.m. Eastern / 6:30 p.m. Pacific. Join the online event here. I hope to see you there.
Unlike too many (i.e. most) of our politicians, I’ll admit a mistake. New evidence has recently emerged—well not really since the evidence was always there, I just failed to notice it—that I incorrectly identified one of the bears on the cover of my audio book. Here’s how that happened.
In my last post, I noted that 32 Chunk is at lower left on the cover. I based the identification on the bear’s swept back ears, face, and light bulb shaped body, all traits that I associated with Chunk in his younger days. However, I neglected to note the prominent wounds on the bear’s forehead and right side, which Chunk did not have when the photo was taken.
Typically, only the largest wounds produce lasting and conspicuous scars on brown bears, and you wouldn’t be able to pick this bear out of the crowd at Brooks River today by looking for remnants of the particular injuries in the photo. They would blend with the bear’s many battle scars, if they were visible at all.
Nevertheless, wounds are important identifying characteristics on bears while they last. The wounds on this bear reveal it’s not Chunk but the mighty 747.
2011, the year of the cover photo, was the first year I remember 747 ballooning into a large bear, but he had not yet achieved the girth of a champion. During 2011, his place in the hierarchy was constantly challenged by two larger bears—856 and 814 Lurch—who frequently displaced 747. Lurch was a bold competitor and even went so far as to steal salmon from 747. 856, meanwhile, would continue to displace 747 from fishing spots and mating opportunities for most of the next ten years. Perhaps 747’s ear position and facial expression in the cover photo is a reaction to the approach of one of his rivals.
Several people correctly identified 747 on the audio book cover for my Guess the Cover Bear contest, so I thought it only fair to offer that group a chance to win a copy of the audio book. Congratulations to Megan Meier from Maryland. Megan will receive a free copy of The Bears of Brooks Falls.
Thanks to everyone who participated—and if you won previously and haven’t reached out to claim your prize, please check your email.
Most of the bears who use Brooks River in Katmai National Park are known individuals that return to fish for salmon year after year. Many return for their entire lives, and their stories are an integral part of my book, The Bears of Brooks Falls. Last month, I invited readers to guess the identities of the bears on the print and audio covers. I placed entrants into separate drawings for the chance to win free copies of the print and audio book as well as a personalized signed copy of the print book. Here are the answers and the lucky winners.
On the print book cover, two of the three bears are fairly distinctive yet all three are legends.
Sitting below the falls is everyone’s favorite example of patience and efficiency, 480 Otis. His face is a bit obscured due to the camera angle. The photo was also taken before he acquired a bit of a wonky right ear, but you might recognize his classic Eeyore-like posture.
Standing on the lip of the falls at upper left is 6 Headbob, a bear identified as a young adult male in 1988. When I first saw him in 2007, Headbob was a large and skilled angler who had free access to his preferred spot on the lip. (I do wonder how he would’ve fared if he had to compete with Grazer this year.) Headbob was one of the first bears to teach me about longevity and survival for older individuals in this long-lived species.
The other bear on the lip is difficult to identify. In this photo he’s a young adult soon to mature into one the river’s most dominant bears. It is 856. Starting in 2011, he reigned as the river’s most dominant bear for most of a decade. No one predicted his rise to the top of the hierarchy. Even though 856 took a slight step back this summer and began to yield to the mighty 747, it may be many years before we encounter another bear with a similar combination of his size, assertiveness, and fighting skills.
Now to the audio book cover. At upper right is 489 Ted and at lower left we see 32 Chunk. Ted is recognizable by his triangle-shaped ears and distinctive scar on his left hip.
His scar, notably, is the remnant of a large wound he received in 2007. Fair warning: the video is gasp worthy. Ted showcased a bear’s ability to get on with life despite pain.
Chunk is a bit harder to identify. In this photo, he has no obvious distinctive features like Ted. Instead, I recognize him by his face and body shape. Even during his subadult and young adult years, Chunk always had a pear-shaped body.
Since Ted’s wound is relatively small in the cover photo and he was last seen in 2013 and since Chunk appears to be a sizable young adult, then this places the photo sometime during 2011 – 2013.
Only one person correctly identified all the bears on the print book cover. Congratulations to Mariah Denhart from California for correctly identifying all the bears on the print book cover. She receives a personalized signed copy from yours truly. No one correctly guessed the both cover bears on the audio book, so I placed all entrants from that category with at least one correct ID into a separate drawing. Congratulations to Jolene Nagle from West Virginia who wins a free copy of the audio book. Lastly, congratulations to Mike Hass from Oklahoma who wins a free print book from a drawing of all “Guess the Cover Bear” entrants. I’ll be touch with each winner via email with more details.
Thank you to everyone who participated. I’ve been overjoyed by the positive notes and reactions that have been sent my way about the book. Most importantly, though, I hope it enhances your understanding of Brooks River, its bears, and your bearcam watching experience on explore.org. May it inspire you to protect this special place for bears, salmon, people, and all the area’s inhabitants now in the future.
PS: Bearcam fan and sometimes National Park Service volunteer Stacey Schmeidel has been leading a book club about The Bears of Brooks Falls this summer. The next meeting is September 11 when the club discusses Chapter 11: Keystone. Please sign up for the Zoom meeting if you want to participate.
We’re in the thick of the bear-watching season at Brooks River in Katmai National Park, Alaska, and I returned only recently from a two week trip to the river to host live bearcam events. I didn’t get enough sleep during that time, yet the fatigue was a minor inconvenience so I could experience the bears in person, and more importantly, share that experience with people around the world. Please tune into the bearcams every day for perhaps the best, live wildlife-watching experience on the internet.
Katmai’s rangers and I have many live bearcam events in store for the rest of the summer. But if you are looking for a different type of bear-related event, I’m excited to join two great bookstores on opposite corners of the United States for talks about my book The Bears of Brooks Falls: Wildlife and Survival in Alaska’s Brooks River.
On July 22 at 9 p.m. Eastern (6 p.m. Pacific), I’m joined by bearcam fan, national park volunteer, and fearless book club leader Stacey Schmeidel for a Q&A with Third Place Books in Lake Forest Park, WA. Register for this event.
On July 29 at 6 p.m. Eastern (3 p.m. Pacific) I’ll talk with Heidi Carter, owner of Bogan Books in Fort Kent, Maine—the most northeastern bookstore in the United States. Join this event on the Bogan Books Facebook Page.
See you then.
Brooks River in Katmai National Park is unique among bear watching sites, because its bears are known individuals with life histories so well documented that several are veritable internet celebrities. Many return to Brooks River year after year, some for their entire lives, a phenomenon we can watch on the bearcams. At Brooks River, bears are not anonymous wildlife, but unique individuals that we can know. Perhaps no other place offers the public the same wildlife watching opportunity.
Many of these same bears feature prominently in my book, The Bears of Brooks Falls. I explore how Otis and 747 satisfy their profound hunger, how 856 establishes and maintains his dominance, how 402 and other female bears navigate the mating season, and how mother bears like 273 nurture their vulnerable cubs.
Since watching the lives of individual bears is a focus of many bearcam fans, I’m frequently asked, “Mike, which bears are on the cover of your book?”
I’ve steadfastly refused to answer, until now that is. I’ll answer, I promise, but you’ll have to do a bit of work first, and perhaps win a copy of my book in the process. Here’s how.
- Guess the identity of the bears on the print and audiobook covers.
- Submit your answers.
- Wish yourself good luck.
Three prize categories will be awarded. *
- Correct answers to the identities of bears on the print book cover will be entered into a drawing to receive a personalized signed copy by the author of The Bears of Brooks Falls.
- Correct answers to the identities of bears on the audiobook cover will be entered into a drawing to win a free copy of the audiobook of The Bears of Brooks Falls.
- Everyone who submits answers, whether correct or not, will be entered into a drawing to win a free copy of the print book.
If you feel a bit unsure about which bears are on the book covers, here are some hints to consider.
- On the print book cover, one of the bears hasn’t been seen at Brooks River in many years and is presumed deceased. The other two continue to use Brooks River, now as older individuals.
- On the audiobook cover, only one of the bears was identified at the river in 2020. The other has not been seen since 2013.
- Neither the print or audiobook cover photos were taken within the last seven years, but they were taken after 2005.
- All the bears in the photos are male.
- No bear is on both covers.
- All the bears have their own page on the Katmai Bearcams Wiki.
Katmai National Park’s The Bears of Brooks River: A Guide to Their Identification, Lives, and Habits is an excellent resource to peruse, although it also may be worthwhile to browse an older version (look for those on Bears of Brooks River on npshistory.com).
Submit your answers through July 20, 2021 and good luck!
*The giveaway is open to U.S. residents only.
Bearcam is back for 2021, and while it’s still very early in the season several bears—including Grazer, Holly, and their yearlings—have made an appearance. As Rangers Naomi Boak and Lian Law discussed with me during our Welcome to Bearcam live chat, there are many fascinating storylines to follow this year. At the risk of offering a shameless plug, my book, The Bears of Brooks Falls, explores many of those stories too.
A dedicated book club has sprung up to discuss the book. At the end of each meeting, participants answer one question: If you could ask the author anything, what would be? Below, I’m happy to answer those questions. If you are interested in joining the book club for their next discussion on June 19 via Zoom, please sign up.
Questions from the club’s discussion of Part One: Creation and Discovery (May 29, 2021)
Can you clarify WHY there used to be fewer bears at the falls? In the past, were they hazed away? Did they stay away from the falls because anglers were given priority there?
In Part One of my book, I discuss the events that led to the proclamation of Katmai National Monument in 1918 and the monument’s evolution into one of the largest national parks in the United States. Bears were not a major tourist attraction at Brooks River until long after Brooks Lodge was established. It wasn’t because anglers were given priority. It was because the bear population was much smaller than today. The national monument was expanded in 1931 to include areas such as Brooks River to protect habitat for wildlife like bears, but:
By all accounts, few bears used the river when Brooks Lodge first opened for business in 1950. Bears and any type of bear-management activities were absent from the reports of the first rangers stationed at Brooks Camp. Ranger Russell Todd, for example, never saw a bear on foot in the summer of 1954. The presence of people alone was apparently enough of a deterrent to displace bears from the river except at night. In 1957, biologists conducting salmon research at Brooks River for the US Fish and Wildlife Service reported bears “loudly evident” every night during September at the salmon- counting weir strung across the head of the river.
How many bears lived within the monument at that time remains an open question, but it was likely not many. The population may even have been at a nadir, the result of decades of heavy hunting pressure near the monument and, I suspect, the lingering effects of the 1912 eruption. After a two- summer biological investigation of the monument in 1953 and 1954, Victor Cahalane reported: “It is impossible to make even a rough estimate of the population of bears in Katmai National Monument.” Yet he tried. According to his and other anecdotal sightings, including one from a pilot who claimed to have seen 60 bears along Savonoski River in early September 1954, Cahalane ventured that about 200 bears lived in the monument.
Steady levels of salmon and a reduction in hunting pressure outside the monument were probably the main factors that allowed the area’s bear population to slowly increase, but at Brooks Camp people inadvertently helped accelerate the bears’ use of the river. By the end of the 1960s, a small and growing contingent of bears had become accustomed to the easy access to unsecured food at nearby garbage dumps, the lodge’s burn barrels, and unsecured supplies. By the mid- 1970s, Brooks Camp had become well known as a place to find at least a few bears, and several had begun to fish in the river during the day when people were active. (Pg. 172-173, The Bears of Brooks Falls)
I will add that over the last 40 years, salmon runs in the Naknek River watershed have been quite strong and that, perhaps more than anything else, has allowed the bear population to increase in the park. Additionally, during much of that time, park staff management have emphasized minimizing bear-human conflicts. The experience of cubs that accompanied their mothers to Brooks River may now consist largely of relatively benign contacts with people. This probably allowed the number and proportion of adult bears tolerant of people to increase.
It sounds, from Mike’s description [in Chapter 3 — Ramble], that the outlet of Brooks Lake into Brooks River is pretty shallow. Could global warming threaten the snowfall on the mountains, dropping the level of the lake and halting the flow of the river? If so, could that be a risk in the near future?
Although I can only provide a speculative answer, and while Lake Brooks will be affected by a warmer atmosphere, its water flow may not change appreciably. Lake Brooks occupies a deep basin that is almost completely below the water table of the surrounding land. There are no glaciers in its headwaters, unlike nearby Naknek Lake, so it’s already adapted in a sense to a hydrology that is highly influenced by annual precipitation. Snowmelt is only one influence. After most of the snow melts from the watershed in late spring, then summertime rain seems to have the biggest influence on water levels in the lake. Wetter summers can raise lake levels more than a foot compared to dry summers. Importantly, much of its water is sourced from spring-fed streams and springs under the lake surface. So, even during drought years, the lake basin experiences some recharge.
Climate change is certainly altering Katmai’s landscape, both the land and water. In 2019, we saw the impacts of a very hot, dry summer on Brooks River. Water levels were quite low and water temperatures were quite hot during an early July heat wave that year. However, water continued to flow through the river, albeit at a reduced level.. That’s just one year, though. By the end of the century—especially if we don’t get our act together and reduce our greenhouse gas emissions as quickly as possible—the summer of 2019 will be one of the coolest of this century. Droughts and heat waves may become the norm in Katmai. For more information on the present and future of Katmai’s climate, please see chapter 17 of The Bears of Brooks Falls.
Can you clarify the distance from Brooks River to Margot Creek? Is it common — or uncommon — to see “our” cam bears at Margot Creek?
The shoreline of Naknek Lake between Brooks River and Margot Creek is about 13 miles, well within a day’s walk for a brown bear. If a bear takes a few shortcuts through the forest, then the walk is closer to 10-12 miles.
Several identifiable Brooks River bears use Margot Creek in August including 402, 435 Holly, 480 Otis, and 856. I would not be surprised if there are others well. But, salmon are dispersed widely in central Katmai in August when bears fish at Margot Creek. Unlike early summer and early fall when Brooks River is the only place to fish, bears have many other alternatives to Margot Creek in mid summer so not all Brooks River bears need to go there.
Can you talk about your research process? The book draws on your personal experience — but it clearly draws on extensive research, too.
When I began drafting the manuscript, I thought most of my research was finished since I had to study a lot to prepare programs and talk about bears when I was a park ranger at Katmai and through my current job at explore.org. That head start was helpful but not thorough enough. It was merely the foundation to build upon.
As I wrote, I wanted to be sure that my facts and conclusions were backed up by personal observations, experience, and the best available science. While working on the manuscript, I probably spent half my time reading research and half my time writing.
I began writing each chapter by outlining it. Then after I established what I wanted to write about and the stories that would add depth to the facts, I read or skimmed through the relevant books and scientific papers that I saved previously to establish the basic facts that I wanted to include and confirm what I thought I knew. This led me down many rabbit holes. I probably read dozens of papers for some chapters, especially Chapter 4 on hibernation. Tracking down specific facts and, hopefully, ensuring that I represented them accurately in the book was a tedious yet necessary task. Readers deserve no less.
Not a bear question, but a question for you as an author: What did it hurt to leave out of the book? What did you have to omit that you wish you’d been able to keep?
Quite a lot, actually. For example, I drafted chapters on glaciation and the evolution of Brooks River, but after consulting with an editor I decided to cut those. They weren’t a great fit for the narrative I tried to build. I also wanted to include the story of Holly adopting a yearling 503 in 2014 but couldn’t find the right place for it when I outlined the book. I considered using that story as the framework for Chapter 5: Family, but since adoption in bears is so uncommon I thought it best to focus on a bear whose maternal experiences were engaging yet more typical. That’s how I settled on 273 and her cub for Chapter 5. I’m happy with the final result of that chapter, yet I still wish I had found a way for Holly to be a part of it.
Questions from the club’s discussion of Chapter 6: Mating Season (June 6, 2021)
What if a female [bear] doesn’t want to mate? How much “say” does she have in the decision?
The female bear can’t control estrus or the signals that indicate to males that she is in estrus. However, female bears seem to have a lot of say in the timing of copulation. Although male bears are much larger than females, I’ve never seen a male bear force himself on a female bear. Instead, he doggedly follows her until she is ready to accept his advances. I also wonder if prolonged courtship can provide female bears with the chance to shed a suitor that they do not prefer. As I write in the book, a bear’s sense of smell is so powerful that a female can’t hide from a male. But, since mating opportunities are so limited for males, it’s not uncommon for more than one male to catch the scent of an estrous female. A prolonged estrus cycle coupled with a lengthy courtship could increase competition between males—an unconscious way for her to attract the most “fit” mate.
What is the ratio of males/females at Brooks River?
It hovers near 50:50, but last year there were more females than males. Because large adult male bears occupy the most productive fishing spots at Brooks Falls, it can sometimes seem like there are more males on the river than females. In July 2020 park bear monitoring staff identified slightly more female bears than males (29 adult females, 22 adult males, 14 subadult females, 11 subadult males).
Can you talk a bit about inbreeding? It seems like a lot of the bears we see mating are likely related to each other…
There’s only one confirmed case (through DNA analysis) of consanguineous couplings (inbreeding) between related bears at Brooks River.
24 BB was a very dominant male bear at Brooks River from the late 1990s through 2007. He was the equivalent of 856 during that time, and because of his dominance few bears would ever challenge him for fishing spots or for access to estrus females. BB sired a litter with the female 209. Bear 402, who still uses Brooks River, was one of the cubs from that litter born in 1998. 24 BB then sired a litter with 402. The offspring from the 402/24 relationship were weaned by 402 and identified as independent bears, but have not been seen in many years. I should note that this is common among subadult bears and their absence may not be reflective of interbreeding between a father bear and a daughter bear.
The limited DNA analysis of bears in 2005-2007 did not document any litters from a mother/son relationship. I think it’s unlikely that a bear could mate with its mother for a couple of reasons. 1. Male bears compete for the opportunity to mate with females and a larger, more dominant male would certainly outcompete a younger male bear for access. So while a young male bear is mature enough to mate around age 6, he’s still quite small compared to older males. 2. Young male bears often disperse away from their mother’s home range, and consequently their ranges as adults might not overlap. Mother bears remember who their offspring are too, and mom is often intolerant of the approach of her former cubs (we sometimes see a mother charge her former cubs, even years after family breakup, almost as if she is saying, “I told you to leave. Now stay away”).
Katmai’s brown bear population is quite large and robust. About 2,200 bears were estimated to live wholly or partly within Katmai National Park and Preserve in 2007. Although, we don’t know its true frequency, inbreeding between bears is probably uncommon here since the population is so large.
Why do mating males want to keep females in sight? It seems like all this following females around would distract males from eating and getting fat.
Courtship between bears isn’t always a prolonged process. In fact, sometimes bears couple soon after meeting. Potential male suitors, therefore, need to guard access to their prospective mates, lest they lose a rare mating opportunity.
The pursuit of mating opportunities certainly distracts male bears from other life tasks like fishing for salmon. I remember one July when 856 seemed like he didn’t stop courting females for the entire month. While the other males at the river got their fill of fish, 856 fished only occasionally because he was more interesting in reproduction. Near the end of July, he looked well muscled from the exercise of the pursuit but looked as though he had little body fat.
856 often spends a lot of time courting females in early summer and less time fishing compared to many other adult bears. He can afford to do so because his high level of dominance provides access to fishing spots wherever he goes.
“Survival of the fittest” is often thought to refer to athletic fitness or survival instincts, when it is more accurately framed in terms of reproductive fitness. Perhaps the male bears who have the energy reserves and stamina to court female bears for long periods of time with little food are the most reproductively fit. It’s also important to consider that the bears’ mating season ends in early summer, just when food becomes plentiful in Katmai, so a male who doesn’t eat much in June has ample opportunities to make up for it during the next few months.
Questions from the book club’s discussion of Chapter 14: Boundaries (June 12, 2021)
Is there any research showing how reduced attendance during the 2020 pandemic affected the salmon and/or the bears?
As far as I know, there’s nothing publicly available yet. However, biologists at Katmai National Park expanded the bear-monitoring program last year to collect data that might help answer that question. It was an unexpected research opportunity to observe bears at Brooks River at a time of year when typically it is loaded with people.
Certainly the lack of people at the river in 2020, especially when the camp remained closed to the public, allowed bears more space to fish. The greatest influence on the distribution of bears last year, though, was salmon. The record run of sockeye salmon was overwhelming and it provided bears with ample feeding opportunities throughout the river. In a year with fewer fish, I don’t think we wouldn’t have seen bears using the lower river in early summer as much as they did in 2020, no matter how few people visited.
The bears at Brooks are perhaps more human-habituated than other bears. And yet, as 854 Divot’s story proves, they do wander outside the boundaries of the park, where they will encounter humans who don’t operate according to park rules. Can you offer some reassurance — or some insight — about how their human habituation might affect their fate outside park boundaries?
Habituation at Brooks River provides a bear with advantages. It allows access to parts of the river that may otherwise be off limits if the bear isn’t tolerant of people. At Brooks River, people are especially tolerant of bears too through both attitude and regulations designed to protect bears.
Outside the park, they may not encounter the same tolerance. Having a bear prowling outside your cabin at Brooks Camp is one thing. Having it do so near your children and pets is another.
If a habituated bear wanders into King Salmon, for example, its tolerance for humans may lead it to temptation in the form of unsecured food and trash. A habituated bear could more easily become conditioned to seek human foods in that situation. Bears encounter much greater risks around people in those places than they do at Brook Camp.
Some biologists I’ve spoken to speculate that habituation could be context specific. That is, a bear might be able to learn that people in one location are tolerant while people in another location are dangerous. I think this is plausible but I’m not yet convinced it works that way for most bears. Further research is needed.
August 6, 2015. I stand at the crest of Katmai Pass, remarkably alone in an exceptionally quiet place, not having seen or spoken to a person in five days. Surrounded by wildness, I couldn’t help but think of the transformational moments that occurred here about 100 years before.
While wildlife such as brown bears take center stage in Katmai National Park today, volcanoes originally placed Katmai on the world map. Each national park is unique, but Katmai stands apart from all others for a landscape that did not exist before June 6, 1912.
An extinct fumarole in the Valley of Ten Thousand Smokes.
On June 6, 1912, around 1 p.m. in the afternoon, Novarupta volcano exploded at the head of the isolated Ukak River valley. The eruption continued for 60 hours, plunging the region into darkness. It was the largest eruption of the 20th century and the fifth largest in recorded human history. Novarupta unleashed roughly 4 cubic miles of ash and 2.6 cubic miles of pyroclastic flows. In total, this represents 3 cubic miles of underground magma, an output greater than the eruption of Krakatoa in 1883 and 30 times more than the eruption of Mount Saint Helens in 1980. The eruption drained a magma chamber underneath the 7,600-foot Mount Katmai, creating a 2,000 foot deep caldera, and flooded the area near Novarupta in hundreds of feet ash and pumice.
In the aftermath, the Katmai area, particularly the mainland Pacific coastline and interior regions near Mount Katmai became uninhabited. What seemed to be a wasteland, however, would soon inspire the movement to establish Katmai National Park.
Robert Griggs was a professor of botany at Ohio State University when, in 1915, he led a National Geographic Society expedition to explore vegetative recovery on Kodiak Island. About of foot of ash fell on Kodiak in 1912 and Griggs found the town “bleak and desolate” with only tall shrubs, trees, and hardy perennials surviving above the ash when he visited in 1913.
Upon his return to Kodiak in 1915, however, Griggs found a wholly different place. The island was verdant. As he recalled, “[I] could not . . . believe my eyes. It was not the same Kodiak I had left two years before. . . . I had come to study the revegetation, but I found my problem vanished in an accomplished fact.” Griggs concluded the foot-deep ash, rather than killing the hardy perennials underneath, served as a mulch that retained soil moisture and suppressed competition for space and nutrients.
Instead of remaining on Kodiak watching the grass grow, Griggs decided to explore the area closer to the eruption center with his remaining time. Landing in Katmai Bay with two expedition companions, Griggs discovered a strikingly different scene than the greenery of Kodiak, one that he described as an “entrance to another world.” It seemed the entire world was covered in ash. Traveling conditions were so difficult—they routinely encountered thigh-deep quicksand and dangerous river crossings—that the team could not ascend far up the valley. The little he saw, though, convinced Griggs that the area was worthy of further exploration.
The next year, 1916, Griggs returned determined to reach Mount Katmai, then thought to be the sole source of the 1912 eruption. His larger and better-equipped expedition slogged up valley that July and eventually climbed Mount Katmai, becoming the first people to gaze into its 2,000-foot deep caldera.
While on the caldera rim, Griggs thought he saw wisps steam wafting from the far side of the volcano. He would soon discover what lay on the other side but was wholly unprepared for what he saw. I’ll let this excerpt from my book, The Bears of Brooks Falls, describe what happened next.
July 31, 1916 was a tiresome day for Griggs and his two partners, Donovan Church and Lucius Folsom. Their legs remained fatigued from their second Mount Katmai climb and the ash beds offered little firm ground to stand on.
Not far from the highest point in Katmai Pass, Church gave out, “incapacitated by too many flapjacks at breakfast” and waited while Griggs and Folsom continued onward. Griggs’ first glimpse through the pass didn’t hint of much worth investigating except more ash and pumice, but just as he considered turning back a tiny puff of steam caught his attention. This fumarole, or volcanic gas vent, wasn’t particularly large, but the day was damp and chilly so Griggs used it practically, warming his hands in the condensing steam. Shortly afterward he spotted another plume rising from a larger fumarole in the distance. Curiosity hastened Griggs forward and he climbed a small hillock for a better vantage.
“The sight that flashed into view . . . was one of the most amazing visions ever beheld by mortal eye. The whole valley as far as the eye could reach was full of hundreds, no thousands—literally tens of thousands—of smokes curling up from its fissured floor.
“After a careful estimate, we judged there must be a thousand whose columns exceeded 500 feet. I tried to ‘keep my head’ and observe carefully, yet I exposed two films from my one precious roll in trying for pictures that I should’ve known were impossible. For a few moments we stood gaping at the awe inspiring vision before us…It was as though all the steam engines in the world, assembled together, had popped their safety valves at once and were letting off steam in concert.”
With the day waning and Church still waiting on the other side of Katmai Pass, Griggs and Folsom had little time to explore further, but this was truly virgin territory. No one had set foot in this valley since the eruption irreparably altered it. No one had felt the hot earth under their shoe leather or warmed their hands next to the fumaroles. No one had seen the eruption’s epicenter, the steaming dark gray lava dome Griggs would later name Novarupta. After roughly estimating the number and extent of visible fumaroles, he christened the landscape the Valley of Ten Thousand Smokes.
Griggs didn’t return to his base camp until very late in the day. Despite his fatigue he found sleep impossible, his mind whirling with thoughts about the valley he had just found. The landscape was “unseen and unsuspected…until this hour…I had yet only a very inadequate conception of the place we had discovered, but I had seen enough to know that we had accidentally discovered one of the great wonders of the world. I recognized at once that the Katmai district must be made a great national park, accessible to all the people, like Yellowstone.”
From the 1922 book The Valley of Ten Thousand Smokes by Robert Griggs.
Griggs returned home later that summer and began immediately to lobby for a national park in the Katmai region. With the support of the National Geographic Society and their contacts in the federal government, President Woodrow Wilson proclaimed Katmai National Monument in 1918.
Standing in Katmai Pass about 100 years later, I thought of the moments that Griggs and Folsom experienced as they wandered into the Valley of Ten Thousand Smokes for the first time. With the heat trapped in the ash and pumice having almost completely dissipated, there are no fumaroles in the pass today. Large lava flows from the southwest flank of Mount Trident, even fresher than the 1912 deposits, constrict the valley leading to the pass from the south. A wrinkled cryptogamic soil covers much of the pumice, anchoring the airy gravel in place. The veneer of glaciers on the nearby volcanoes has thinned as the climate continues to warm.
Still, the scene remains remarkably similar to that in which Griggs experienced. No roads or maintained trails snake their way into the Valley or the pass. The views are unimpaired. No light pollution reaches its night skies. In calm weather, your footsteps and heartbeat are often the only sounds—a quiet so immense that the rip of a jacket’s zipper feels like an intrusion. The Valley of Ten Thousand Smokes is contradictory, both wholly different and very much the same as it was when it inspired Griggs to pursue permanent protection for a unique landscape on the face of the Earth.
In 1912, the Alaska Peninsula was forever changed. Rarely has a single event—one that humans witnessed—catalyzed the creation of a national park. If you’ve been fortunate enough to experience the sublimity of wild landscape then perhaps you’ve also experienced something akin to what Griggs felt at Katmai Pass in 1916. The legacy of the discovery of the Valley of Ten Thousand Smokes continues to shape the history of Katmai.
Looking north in Katmai Pass near the spot where Griggs and Folsom found their first fumarole. The Valley of Ten Thousand Smokes is found just beyond Mount Cerberus at center.
Taken in 1919, “Waiting for Supper to Cook” is perhaps the most iconic historic image of the Valley of Ten Thousand Smokes. From the 1922 book The Valley of Ten Thousand Smokes by Robert Griggs.
The Valley of Ten Thousand Smokes near the confluence of Knife Creek and River Lethe.
Many years ago, inspired by the complicated and fascinating intersection of bears, salmon, and people at a most unique place, I conceived the idea of a book that captured the story of Brooks River in Katmai National Park.
Today, I’m pleased to announce that The Bears of Brooks Falls: Wildlife and Survival on Alaska’s Brooks River is now available.
Part one of The Bears of Brooks Falls explores the establishment of Katmai National Monument, from the moments preceding the largest volcanic eruption of the 20th century to the discovery of the surreal Valley of Ten Thousand Smokes. These events inspired the creation of Katmai National Monument and, soon after, the efforts to expand the park for wildlife like brown bears.
Today, Katmai is most famous for its brown bears. Part two is devoted to their lives as well as the salmon that the bears depend on for their survival. I explore the marvel of the hibernating bear, discover Brooks River from a cub’s perspective, and follow the tribulations and growth of young bears recently separated from their mother. I also ponder how Katmai’s brown bears experience reproduction, competition, hunger, and death.
Few organisms are as important to an ecosystem as sockeye salmon are to Brooks River. These fish face tremendous obstacles and challenges. From freshwater to the ocean and back again, they travel thousands of miles, running a gauntlet of predators to fulfill their destiny. The journey ends when they sacrifice their lives to reproduce. Salmon are Katmai’s keystone, driving Brooks River’s productivity and significance.
In part three, I examine modern humanity’s influence over Brooks River. Humans may be the river’s biggest wildcard. Climate change looms large over the land and seascapes, and people alter the behavior of the bears that make the scene so special. The infrastructure needed to support thousands of visitors and their recreational activities invites conflict with bears. Managing bears and people in such a small area is especially challenging, provoking a decades-long and often emotional debate about the river’s future.
Brooks River’s bears live in a land that straddles the border between the wild and human realms. Their lives are intertwined with ours, and as a result Brooks River is a microcosm for many of the issues facing our national parks. No book has captured this story before.
Order your signed copy through the Katmai Conservancy, the official non-profit partner of Katmai National Park, and join the book release live event on March 9 at 8 pm ET / 5 pm PT on explore.org’s live events channel.
I’d also love to know what you think of the book. Drop a comment in response to this post, email me, or post a review on the websites of major booksellers.
Origin stories seem to be almost requisite for superhero movies, even for well-known characters. (Like, we all know by now that a radioactive spider bit Peter Parker and Bruce Wayne witnessed the murder of his parents; so perhaps the next time Hollywood decides to reboot their tales, maybe just skip over those parts?) Landscapes, on the other hand? Their origins are not investigated nearly enough.
In my last post, I introduced the glacial origins of Brooks River, perhaps the most iconic wildlife viewing site in U.S. national parks. This was far from the full story though. After glaciers sculpted the land, a series of dramatic changes occurred as the river evolved into its current form. In this online chapter of The Bears of Brooks Falls: Wildlife and Survival on Alaska’s Brooks River, I investigate the river’s most recent origins. Brooks River is a superhero of a landscape, providing a home for bears, salmon, and people for thousands of years.
In the coming weeks, please check my blog and Twitter feed to find details about how to order signed copies of The Bears of Brooks Falls. And, be sure to ask for it at your favorite independent bookstore. The book ships out March 9, 2021.
Throughout the years I spent as a ranger at Brooks Camp, I enjoyed exploring the thin ribbon of beach bordering Naknek Lake, especially in spring when the lake was near its annual low point. The beach stretching north from the mouth of Brooks River is one of the most inviting and extensive on Naknek Lake. It’s also temporary—a symbol of the lake and river’s continued evolution.
On a prime May evening in 2015, I make time to explore the changes wrought on the beach by the prior winter’s wind and waves. I exit the line of alder and spruce near the visitor center and walk toward a lake that is dramatically lower than the previous fall. Two wrack lines, built with airy pumice and driftwood flotsam, identify former high water stands from years past. The uppermost borders the very edge of the vegetation line and marked the high water mark in 2012, a year when the lake, or at least its wind-driven waves, rose to the beach’s upper boundary. The other, where the lake reached its maximum volume in 2014, is more than 10 feet closer to the water and a foot lower in elevation. Even with my eyes closed, when walking to the water from the tree line I could find the wrack lines by sound and texture. Pumice and small branches of driftwood roll and crunch underfoot like broken pieces of hard styrofoam. Gravel and sand, in contrast, feel heavy and less hollow.
When my feet reach the water’s edge, I turn right and walk south, approaching the river by paralleling a set of early season bear prints. I stop and face the river where it flows through a narrow channel barely a stone’s throw wide. I’m isolated at the end of a gravel bar, where the river finally meets the lake, and unable to go farther without wet feet. Otter tracks crisscross the sand, while on the opposite shore terns, mergansers, and gulls rest and preen on a bar of pebbles jutting into the shallow lake. They keep a wary eye on me but make no move to fly.
The beach and the gravel bars adjacent to the river mouth are altered by Naknek Lake’s predictable cycle of swelling and shrinking. It is widest in early spring after months of sub-freezing temperatures reduce the lake’s inflow to a trickle, and thinnest in early fall after a summer’s worth of rain, snowmelt, and glacial runoff fill the basin. In late summer, I couldn’t come close to approaching this area without swimming. I stand on dry ground about six feet lower in elevation than last autumn’s wrack line. A multi-year time lapse of this spot would record an annual cycle—the lake swelling with onset of spring thaw and shrinking when widespread freezing temperatures return in autumn. When flooded this spot is patrolled most often by hungry bears who swim in search of carcasses of spawned-out salmon.
Wind-driven waves periodically reorganize the beach and river mouth. Temporary longshore currents, driven by strong easterly winds, purge sediments from the lakeshore south of the river and carry them northward. Storms shoal the unconsolidated sand and gravel into bars and spits, altering the flow of the river where it meets the lake.
Although these changes can be dramatic, the winter of 2014-2015 brought only a subtle reorganization to the river mouth. More sediment was deposited on a gravel bar near the tree line neighboring the lodge. On the south side of the river, a substantial spit grew a few feet northward. This spit arcs upstream into the river to create a calm, protected cove where waves do not reach, a convenient place for Brooks Lodge and National Park Service staff to moor boats away from the lake’s waves. I wondered how far this fan of gravel might one day extend. It’s grown a little wider every year of my observations.
An iteration of the spit and sheltered lagoon behind it has featured prominently at the river for hundreds of years, perhaps longer. In the Alutiiq (Supiaq) language, Brooks River is known as Qit’rwik. Pronounced kettiwick or kittiwick, Qit’rwik is a descriptive word that translates to a “sheltered place on the water.” More generically, a qit’rwik can refer to any lagoon or protected bay that is connected to open water and can provide shelter for a boat.
In September 1940, Mount McKinley National Park Superintendent Frank Been and U.S. Biological Survey biologist Victor Cahalane visited Katmai National Monument. They witnessed Alaska Natives, who traveled from the King Salmon and Naknek area to Brooks River, harvesting salmon. Mary Jane Neilson participated in those harvests and later recalled, “While we were at Qitirwik…Grandma…and our parents would catch fish to split and dry. The men built racks to dry the fish at the mouth of Brooks River on the south shore. Fish racks were still up in the 1950s when the National Park Service became more visible in the area.” Motorboats had replaced traditional mammal skin kayaks by then, but the river mouth, partly sheltered and enclosed by spits of sand and gravel, still provided people a safe harbor from wind-driven waves and a convenient spot to prepare and dry salmon.
Many a qit’rwik’s story is locked in place by fickle, shifting sediments and the evolving nature of Katmai’s lakes. South of the river mouth a small pond hides in the forest. Before the National Park Service constructed a one-lane road to it in 2014, I occasionally visited the Beaver Pond to escape Brooks Camp’s bustle or simply for a change of scenery. Walking south along the lakeshore from the river mouth, a hedgerow of alder, birch, and poplar trees obscured the pond and any resting bears in the vegetation, but the actual bushwhack to it was short when I chose the route correctly.
At first glance the pond is like many others in the area. It is moderately sized and oblong, measuring about 2000 feet east to west and 1600 feet north to south. Beavers, as its nickname suggests, have used it for decades although the pond is not a product of beaver industry. There is no dam to hold its water back nor does much flowing water enter it. The pond is fed primarily by rain, snow, and slow seepage from adjacent marshes.
Perhaps thousands of similarly-sized ponds dot western Katmai and the adjacent Bristol Bay lowlands, most of which are glacial kettle holes, features that form where stranded blocks of glacial ice were surrounded by till and outwash. As the isolated ice melted, they created enclosed basins that filled with water. Despite its superficial resemblance, Beaver Pond is not a kettle either. Its history began in the shifting sands and pebbles along the Naknek Lake shoreline.
The Beaver Pond occupies an open embayment that was once cleaved into the glacial outwash bordering Naknek Lake. At first, it may have been exposed to the full force of wind and waves, not unlike the modern-day beach adjacent to the lodge and visitor center. Strong winds funneling across the Aleutian Range and down Iliuk Arm did not permit the bay to remain open indefinitely, however. Wind stirred waves pushed gravel and sand westward from the raw, highly erodible glacial sediments near the Iliuk moraine. These collected into an overlapping series of northward-growing horsetail shaped spits. Eventually, the bay was encircled and permanently separated from Naknek Lake as the spits migrated and thickened toward Brooks River. The Beaver Pond’s divorce from Naknek Lake may have taken decades or centuries, to finalize. All the while, the growing horsetail-shaped spits created a series of long-lasting qit’rwiks.
The Beaver Pond’s formation is just a small part of a more ancient story, one that explains how Brooks River evolved and how it became an important place for people.
Brooks Lodge and the NPS visitor center sit on a lumpy terrace about 12 feet higher than the highest historical stands of Naknek Lake. From the lodge, the terrace’s geometry is apparent. Shaped by waves on one side while the river carved into the opposite shore, it tapers wedge-like toward the river mouth. This is just one of the many old terraces undulating throughout the river corridor from the Beaver Pond to Dumpling Mountain and upstream to Lake Brooks. At first glance, especially when bushwhacking in the forest’s dim confines, the terraces seem haphazardly placed, but a closer look reveals a roughly concentric shape to many. Between the river mouth and Lake Brooks, their concave faces open toward Naknek Lake and climb in a stair step manner—a series of short, steep rises each topped with a relatively flat bench. The terraces continue dozens of feet up nearby hillsides.
When the large Ice Age glaciers vacated Katmai, a series of glacial lakes began to occupy the excavated basins. Such lakes are far from static and often subject to rapid change, filling quickly and sometimes draining even quicker. Those in Katmai rose far above the modern counterparts; their waters held back by temporary ice dams or raw, erodible, and sparsely vegetated terminal moraines.
Lake Brooks was perhaps the first lake in the Brooks River area to undergo a rapid transformation. At the greatest extent of the Newhalen stade glaciers, 23,000 to 20,000 years ago, ice filled two-thirds or more of Naknek Lake’s basin, extending lobes around the north and south sides of Dumpling Mountain. The southernmost lobe pushed completely across the area now covered by Lake Brooks. When this glaciation waned, Lake Brooks began to fill the void. Unlike today, though, when Lake Brooks feeds Brooks River and Naknek Lake, this first iteration of Lake Brooks didn’t find connectivity with an infant Naknek Lake. It was walled in by ice to the east, mountains to the north and south, and a newly deposited terminal moraine to the west. Ancestral Lake Brooks had nowhere to go but up.
Evidence for its rise is preserved in wave cut terraces that lie stranded on hillsides. The highest such terrace sits near the western end of Lake Brooks. At more than 200 feet in elevation, it is 140 feet above the lake’s modern level. At its greatest height, liquid water likely occupied only the far western end of the Lake Brooks basin and only for a short period of time. Filled to capacity and separated from the Naknek Lake basin by ice, Lake Brooks spilled over the moraine on its western shore and drained west through the Bristol Bay lowlands. At the same time, a proto-Naknek Lake began to form in front of the glacial lobe north of Dumpling.
The ice divide between the lakes was short lived and the lakes merged after the Newhalen-aged glacier receded sufficiently to release Lake Brooks’ water into the Naknek basin. With the ice divide gone, Naknek Lake captured and reversed the flow of Lake Brooks.
Naknek Lake now covers 150,000 acres and is the largest lake wholly contained within a U.S. national park. Six large lakes (Brooks, Coville, Grosvenor, Hammersley, Idavain, and Murray), Savonoski River, Ukak River, and countless small ponds and creeks feed it. Yet Naknek Lake is a shell of its former self. It changed just as dramatically as Lake Brooks, if not more so, although these changes are far from finished.
Naknek Lake currently sits at a modest 42 feet in elevation, but in the wake of glacial retreat, the Pike Ridge moraine at the lake’s west end was a formidable barrier to water. Before any outlet could drain the lake, water had to rise high enough to overtop this earthen dam. It did only after reaching heights not seen before or since. Wave cut terraces and stranded beaches adjacent to the lake exist at 190 feet above sea level in the uplands adjacent to the lake. At full pool, Naknek Lake was as much as a third larger than today. It swallowed half of the Savonoski River floodplain; annexed Lake Brooks (el. 72 feet), Lake Coville (el. 108 feet), and Lake Grosvenor (el. 108 feet); made islands out of Dumpling Mountain and Mount La Gorce; and drowned the future site of Brooks Falls underneath dozens of feet of frigid water. For thousands of years after glaciers left, the lake remained so high that no hint of Brooks River existed.
Slowly, Naknek River’s down cutting reduced the Naknek Lake’s storage capacity. Islands merged. Rivers lengthened. Lake basins separated. All the while, waves carved terraces onto mountainsides during prolonged pauses in the draining. But the future site of Brooks River remained an abyss. Terraces higher than 98 feet in elevation are capped with volcanic ash from an eruption twelve to thirteen thousand years ago, indicating the land adjacent to the modern river mouth was still below as much as 56 feet of glacially cold water at the time.
After Naknek Lake captured its water, the Lake Brooks basin mirrored the changes of greater Naknek Lake for thousands of years until they separated for good between 6,500 and 5,500 years ago. Then, lowering lake levels exposed a dike of igneous rock in the path of the water flowing from Lake Brooks to Naknek Lake. At the surface after thousands of years or subaqueous inconsequentiality, and unlike the veneer of unconsolidated glacial till and lake sediments covering much of the Brooks River area, this bedrock was not easily erodible. Meanwhile, Naknek Lake continued to drain away as its outlet, Naknek River, eroded through the terminal moraine serving as the lake’s dam. The gently lapping water of Lake Brooks lacked the erosive energy to remove its newfound bedrock dam, however. Lake Brooks, perhaps for the first time ever, became locked in place.
Nearly all the dry land surrounding Brooks River today was exposed when the first semblance of a river formed five thousand years ago, but water levels were still high enough that the early river was very short, merely a wide area of slowly flowing water between the diverging basins. Less of a river than a narrow strait, the area quickly became an important resource for animals and people.
The oldest evidence of people known from the Alaska Peninsula comes from a squeeze of land about 75 miles southwest of Brooks River. Ugashik Narrows separates north and south Ugashik Lakes on the Alaska Peninsula National Wildlife Refuge, and is one of the most popular sport fishing destinations in all of southwest Alaska. Evidently, its popularity extends much further back in time. Artifacts at the narrows reach 9,000 years in age, but the first people there may not have been fishing much. Chipped stone tools suggest the first residents at Ugashik Narrows came for caribou, animals that would’ve moved efficiently across the open, tundra-like habitat, browsing on lichens in winter and green forbs in the summer. Instead of swimming across the lakes at Ugashik, the caribou crossed the stream at the narrows. People let the land funnel their quarry.
A similar dynamic occurred at the Brooks River narrows circa 3000 BC. A caribou herd moving toward the river narrows faced a choice: swim across miles of open lake water or follow the land. Caribou are good swimmers, but like many terrestrial mammals they often stay high and dry when given the option. The first people at Brooks River, like those at Ugashik Narrows, knew this well. They followed the migratory herds to the emergent Brooks River or established camps there and waited. Archeological excavations uncovered large stone lances and knives—weapons used to hunt large mammals—from Brooks River’s earliest human inhabitants. Caribou bones within their campsites prove they were successful.
The currently available archeological evidence suggests, curiously, that salmon were not a major food source for the earliest cultures at Brooks River even though salmon may have colonized Katmai’s lakes soon after they formed. Analysis of sediment cores from Nonvianuk Lake north of Brooks River indicate the presence of anadromous salmon there as much as 10,000 years ago, but no direct evidence of this yet been obtained for Naknek Lake so far back in time. The placement of the earliest camps at Brooks River are away from what would have been the water’s edge at the time, so if salmon were present when the first people arrived, perhaps they weren’t abundant enough to target or the strait between the Lake Brooks and Naknek Lake basins was too challenging to fish successfully.
No matter the reason for the lack of piscivory, free passage for salmon through Brooks River was short lived. As Naknek Lake continued to recede, the strait evolved into a river. Approximately 4,000 years ago the lengthening river uncovered a ridge of sedimentary rock less than a mile downstream of Lake Brooks. At first, Naknek Lake remained high enough that barely a ripple tumbled over the hard conglomerate. Perhaps it was unnoticeable to the salmon migrating in the young river. The ripple grew year by year, growing taller as Naknek Lake withdrew. By 3,500 years ago a distinct plunge formed, one high enough to temporarily impede salmon migrating upstream to spawn. Brooks Falls had emerged.
I like to imagine a qit’rwik from long ago, a harbor that perhaps inspired the proper name, Qit’rwik. The former waterfront property hides today within the surrounding forest with artifacts from previous cultures buried in the thickening duff. That qit’rwik foreshadows the fate of Brooks Lodge, the rangers’ cabins, the campground, and the visitor center. Could the newly conceived gravel bars at the river mouth, which seem so ephemeral at first glance, become a future qit’rwik as the river continues to evolve? Some iteration of Brooks River and its adjacent lakes will remain long into the future. It won’t be the same, but it’s far more likely to outlast our cultures than we are to outlast it.
- Brooks River known as Qit’rwik and meaning of word: Helen Lons email to Katmai National Park Staff. 2007.
- In September 1940, Mount McKinley National Park Superintendent Frank Been and U.S. Biological Survey biologist Victor Cahalane visited Katmai National Monument: Norris, Frank B. 1996. Isolated Paradise: An Administrative History of the Katmai and Aniakchak National Park Units. National Park Service. Pg. 60.
- Mary Jane Neilson quote: Neilson, M. J. 2005. The Pelagia Story. Unpublished Masters Thesis. University of Alaska Fairbanks. P. 43.
- Definition of kettle hole: Hambrey, M. and Jurg, A. 2004. Glaciers, 2nd Edition. Cambridge University Press.
- These collected into a series of lengthening beaches, which migrated and thickened toward Brooks River into horsetail shaped spits: Hults, C.P. 2016. Draft Geomorphic Map of the Brooks River Area and Part of the Road to Valley of Ten Thousand Smokes. Natural Resource Report NPS/NRSS/GRD/NRR-2016/. National Park Service, Alaska Regional Office, Anchorage, Alaska. LIDAR imagry of the Brooks River area clearly shows the land’s geomorphology and can be viewed at http://maps.dggs.alaska.gov/elevationdata/#-17339224:8083535:14.
- Age of Beaver Pond: The ages of the spits encircling Beaver Pond are not precisely known, but are most likely young. Some are perhaps fewer than three hundred years old. The elevation of sediments north of the pond is slightly higher than the modern day lake elevation (13 m). The sediments also lack pre-Russian contact archeological artifacts that would indicate an earlier origin.
- Lake Brooks spilled over the moraine on its western shore and drained directly on to the Bristol Bay lowlands: Ibid. Hults, C.P. 2016.
- Timeline of Lake Brooks/Naknek Lake separation and former elevation of lakes: I relied heavily on the elevations and summary in Hults, C.P. 2016. It is also explained in Dumond, D. E. 1981. Archeology on the Alaska Peninsula: The Naknek Region, 1960-1975. University of Oregon Anthropological Papers. No. 21.
- Naknek Lake was certainly lower in elevation than Lake Brooks, perhaps as low as present day: Ibid, Hults. 2016. After Naknek Lake captured Lake Brooks, one last push of ice formed the Iliuk moraine around 20,000 years ago. Discharge from this brief advance formed the broad spruce-covered outwash plain south of Brooks River. Braided drainage channels on its surface indicate the outwash plain was deposited on land, not under a lake, and terraces as high as 68 meters are conspicuously absent along Lake Brooks’ eastern shoreline.
- At full pool, Naknek Lake was as much as a third larger than today: This is my rough guess based on the minimum combined surface areas of Naknek, Brooks, Coville, and Grosvenor Lakes.
- Wave cut terraces at 59 and 57 meters above sea level, respectively, indicate the lake was once much higher and more extensive: Curiously, isostatic rebound is not believed to have significantly altered the elevation of the terraces. Kaufman, D. S., and K. B. Stillwell. 1995. “Preliminary Evaluation of Post Glacial Shorelines” in Geologic Studies in Alaska. Dumoulin and Gray, Editors. U.S. Geological Survey.
- All terraces higher than 30 meters in elevation are capped with volcanic ash from an eruption twelve to thirteen thousand years ago: Ibid, Kaufman and Stillwell. 1995.
- Artifacts at Ugashik Narrows are approximately 9,000 years old: Dumond, D. E. 1987. Prehistoric Human Occupation in Southwestern Alaska: A Study of Resource Distribution and Site Location. University of Oregon Anthropological Papers. No. 36.
I never understood how difficult writing a book can be until I tried it. The brainstorming. The planning. The research. Pitching agents (none were interested). Pitching publishers (I got lucky). The worry. The self-doubt. The first draft. The first, second, and third revisions. The Nth revisions.
Finally, after months and sometimes years, you’re left with a book that you hope will bring some joy and meaning to people and place. Writing The Bears of Brooks Falls: Wildlife and Survival on Brooks River is the culmination of my years of study and observation at one of the most unique and special places in America’s national parks.
Through the drafting process, I wrote, revised, and cut more sentences and paragraphs than I can remember. While revision is often difficult, this is where, for me, the pleasure of writing expresses itself most often. Only through revision can I work through the nonsense and polish the narrative so it reads—I hope—in a logical, intelligent, and engaging manner.
During the drafting and revision process, I cut large sections and even whole chapters from the final manuscript as I discovered new or more concise ways to frame the story of Brooks River. Today, I present a chapter sacrificed for the greater good. Some of it was incorporated into the print and digital versions of The Bears of Brooks Falls, but as I progressed deeper into the manuscript I realized this particular essay needed to be cut so that the narrative could focus more on the brown bears, salmon, and people of Brooks River. I present it here as an online-only chapter for your reading pleasure, illustrated with photos and only lightly edited from its final draft.
Sit back and relax. This is a long read.
In the coming weeks, please check my blog and Twitter feed to find details about how to order signed copies of The Bears of Brooks Falls. And, be sure to ask for it at your favorite independent bookstore. The book ships out March 9, 2021.
I open the gate on the north side of the campground and latch it behind me, careful to avoid the live wires strung horizontally from post to post. The electric fence is an oddity for a national park campground, yet one that is necessary to prevent bears from pressing their noses against the sides of nylon tents.
Outside the campground, following a narrow trail through forest, the world seems to shrink. Thick vegetation limits views of the surrounding landscape. The Dumpling Mountain Trail ascends through a thick understory of head-high grass, shrubby willows, and the corduroyed stalks of cow parsnip. Above the trail hovers a semi-closed canopy of birch and poplar leaves. I’m eager to reach the tree line, which the regional climate keeps at about 1,000 feet above sea level in central Katmai, and explore more open vistas. I march on despite the trail’s steepness.
After forty minutes of brisk travel, I arrive at a small rocky knob where the forest transitions to alder thickets and grassy meadows speckled with the occasional white spruce. Here I stop, not so much because I am winded, but because the perch is one of my favorite spots to loiter.
A complex wilderness panorama stretches to every horizon. A rugged volcanic arc—the ragged crest of the Aleutian Range—marks the eastern and southern skylines. Flanked by reposed Mount La Gorce and the sharp, angular ridges of Mount Katolinat, Naknek Lake emerges from the foot of the mountains and fills much of the nearby low elevations. Directly south, Brooks River meanders through dense spruce forests before its clear water spins in lazy plumes as it mixes with the turquoise water of the glacial lake.
Without catching a plane ride this overlook provides one of the only places to view the river in its entirety. Brooks River and Brooks Falls look insignificant on the scale of the surrounding landscape. Had I first stumbled up Dumpling Mountain with no prior knowledge of the falls, I’d be hard pressed to even notice the line of white foam marking it.
My gaze shifts back to the mountains and lingers on Mount Mageik, a glacially clad volcano about 30 miles to the southeast. Low clouds and precipitation obscure its coalesced summits from this vista on many days, but today’s weather is atypical. Few clouds hover in the sky and the wind is relatively calm. Under bright sun, Mageik’s glaciers seem so pure and fixed, but this is an illusion of time and scale.
I cannot see the glaciers slowly wearing down Mageik, nor will I live long enough to witness anything more than superficial glacial erosion on it, but the view provokes me to ponder the sea of glacial change that shaped this land. The shape of the valleys and lakes below me, the sediments that Brooks River erodes, and even the color of Naknek Lake are all products of glaciers. The full story of Katmai’s glaciers spans a geologic epoch and reaches to land now flooded by the Bering Sea. Until relatively recently, glaciers were this area’s most ubiquitous and prominent agent of geologic change.
Mageik’s glaciers, like all glaciers, are a product of climate, and the Alaska Peninsula has a well-deserved reputation as a damp and chilly place. Climate data for the region is limited, but enough has been gathered from airport and remote automated weather stations to draw some conclusions about the precipitation patterns affecting the area’s glacier formation and growth.
Katmai National Park lies at the head of the Alaska Peninsula, a northeast-southwest trending arc of land jutting into the North Pacific and Bering Sea. The peninsula’s location and orientation expose it to the vast majority of storms bred from the Aleutian Low, a semi-permanent low-pressure system originating near the outer Aleutian Islands. The peninsula’s mountains represent a major topographical barrier to these northeast-tracking storms, forcing warm oceanic air to rise and cool. Water vapor condenses under these conditions and frequently falls as rain or snow. If the day’s weather is damp at Brooks Camp, it is almost certainly wetter along the crest of the Aleutian Range. While inland valleys north and west of the Aleutian Range are spared the full brunt of Pacific and Bering Sea storms, they still may receive about 40 inches of precipitation per year. At higher elevations, though, precipitation increases dramatically. Computer models indicate the volcanic peaks, like Mount Mageik, where snow can accumulate year-round, receive over 98 inches (250 cm) of annual precipitation, enough to qualify as a rainforest if trees could grow there. When global temperatures were as much as 10˚C colder during the Pleistocene Epoch, about 2.6 million to 12,000 years ago, most precipitation over the Alaska Peninsula fell as snow and little melted compared to today. Conditions were ripe for the formation and growth of glaciers.
Thirty thousand years ago, Dumpling Mountain was an island in a glacial sea. Even the overlook where I sit, over 700 feet above Naknek Lake, was smothered by ice. Naknek Lake, the Brooks River area, and nearly all of Katmai were buried. From an ice cap centered over Cook Inlet and Shelikof Strait, glaciers pushed west and north through gaps in the Aleutian Range near Lake Iliamna and Becharof Lake. Ice overrode almost all of nearby Kodiak Island and all of Cook Inlet to the northeast. Glaciers sourced from the volcanic peaks moved through the entire Naknek Lake watershed and over the future site of Brooks River. Almost no land was exposed in Ice Age Katmai except for rare nunataks, isolated mountains projecting above the ice and snow. Off of Alaska’s southern coast, ice extended to the outer edge of the continental shelf, over what is now only open ocean. Glaciers covered three hundred thousand square kilometers of the Alaska Peninsula, an area about as large as Arizona.
Similar scenes were found across the Northern Hemisphere when ice covered as much as 30 percent of Earth’s surface. In North America, ice sheets reached beyond the present locations of Boston, New York City, and Chicago. Glaciers trapped so much water to lower sea levels by almost 400 feet compared to present day. As a result, Bristol Bay and the Bering Sea, now harboring one of the world’s most valuable fisheries, didn’t exist. In their place, low sea levels exposed Beringia, the subcontinent connecting western Alaska and eastern Siberia. In Katmai, there were no bears or salmon. No forests or lakes. No people. Almost no habitat for the living. Ice was the most extensive and dominant force of change.
Amazingly, all glaciers begin as fragile snowflakes. Snow is ice, but it isn’t very dense. By volume, newly fallen snow is ninety percent air, and individual snowflakes break easily as they settle, compress, or become wet. Freshly fallen snow seems inconsequential to rock. Given enough time and the right conditions, though, snow transforms into a force powerful enough to move mountains.
Snow turns into glacier ice in several stages. First, old snow must survive through summer into winter when it can become buried by new snow. Surviving snow has a granular texture and become harder and denser as it compress under the weight of succeeding layers. Typically within a year, snow granules reach a density about half of liquid water and become firn, an intermediate stage between snow and glacier ice. In its transition to glacier ice, firn recrystallizes and changes shape repeatedly under the influences of percolating melt water, freeze-thaw cycles, and the weight of additional snow. Lastly, firn completes its transformation into glacial ice when air is either squeezed out or trapped as bubbles. In temperate areas this process can transform airy snowflakes into dense blue ice in as little as five years.
A block of ice makes not a glacier, however. Take an ice cube out of the freezer, set it on a table, strike it with a hammer and it will fracture. Due to their mass, the ice inside glaciers behaves differently. Glacial ice experiences enormous pressure, so much so that only the upper 100 feet of temperate glaciers are brittle (a fact revealed by the relatively consistent maximum depth of crevasses). Below this depth, pressure from the overlying ice deforms the ice beneath to seal any voids. Cavities at the base of glaciers have been measured to seal as fast as 10 inches per day. A true glacier flows and deforms under its own mass.
The ice is not impervious to liquid water though. Within the glacier, ice remains at or slightly above freezing, and meltwater percolates to the glacier’s base. High pressure at the base of a glacier also causes melting. Meltwater under a glacier acts as a lubricant helping the glacier slide. These factors, combined with gravity’s pull, drive glaciers along the paths of least resistance.
Not that glaciers stop when they encounter resistance. The erosional power of glaciers can substantially transform a landscape. Glacial movement works the earth like a bulldozer and a rock crusher. The ice erodes and entrains rock, sand, and anything else by plucking or abrading it away from the glacier’s base and sides. Stones and debris at a glacier’s bed are especially powerful erosive tools, grinding and crushing rock further. Much of the eroded debris is swept into the glacier’s interior where deformation and sliding eventually carry it into the glacier’s ablation zone, the area on a glacier where ice is lost and all of the previous winter’s snow melts. Advancing glaciers accumulate and eventually deposit thick mantles of till this way.
Over several large stades, or individual advances, glaciers quarried much of the Aleutian Range. Marching toward Beringia, they carried their eroded cargo far from its source and dropped it when climate no longer supported further advance. The largest, oldest, and most extensive glacial deposits in the region are too far away for me to see from the overlook, but when I turn and face southwest I glimpse a fraction of their extent. Beyond the western shore of Lake Brooks, the mountains stop and a broad plain stretches to the horizon. The power and work of glaciers is demonstrated dramatically by the mere fact this area, the Bristol Bay lowlands, even exists.
The nearest communities to Brooks River, King Salmon and Naknek, sit well within the lowlands. It’s a buggy, waterlogged place harboring millions of acres of wetlands and tundra. If the Aleutian Range volcanoes and coastal fjords on Shelikof Strait define Katmai’s ruggedness, then the lowlands represent its smoother alter ego, or so it would appear. Hiking on the wet tundra removes the façade. It is an exhausting slog over sedge tussocks that feel and behave underfoot like piles of water-laden pillows. Wind is about the only thing that crosses the lowlands easily, which provides respite from summer’s vampiric black flies but also brings life-threatening cold in winter.
With exceptions for wind-born volcanic ash, sediments reworked by water, and a mantle of peat and vegetation, the Bristol Bay lowlands were entirely created by the glaciers’ assault on the mountains. These are the oldest glacial deposits in the Katmai region, at least 40,000 years old. The till and outwash is even older near the town of Naknek and the Bering Sea coast, exceeding the age limits of radio carbon dating. Glaciers removed so much material from the mountains and carried it to the coastal plain that half of the Alaska Peninsula is glacially derived. Without these glacial deposits, at twentieth century sea levels the Aleutian Islands would begin fewer than 200 miles from Brooks River and water pouring over Brooks Falls would nearly reach tidewater. Naknek Lake would likely be a marine embayment.
The Ice Age was a time of profound geologic change, when the surface of Katmai and Brooks River was constantly reworked by ice. Glacial movements across the region were inconsistent, however. For tens of thousands of years, in response to a fluctuating climate, the area’s glaciers advanced and receded in fits and starts. Within the last 30,000 years, they plowed ahead many separate times. In between stades, when climatic conditions grew too warm, they stagnated or shrunk. West of the park, near King Salmon and Naknek, only faint hills of low relief trace the maximum extent of the most ancient stades, but younger and less extensive advances have been less affected by post-glacial erosion. Their signatures are scribed over the entire Naknek Lake basin.
The last glacier to entirely fill the area now occupied by Naknek Lake, which I refer to informally as the Naknek glacier, reached its greatest extent no sooner than 23,000 years ago. Part of an advance called the Iliamna Stade, it carried ice 60 miles from its source area on the Aleutian Range to its terminus on the lowlands. Topography funneled this glacier into mountain valleys, but to the west of Dumpling it was unbound and free to deform in multiple directions.
Perhaps the best modern analog for the shape and behavior of the ancient Naknek glacier may be Malaspina Glacier in Wrangell-Saint Elias National Park. Malaspina originates high in the Saint Elias Mountains where extensive ice fields more closely resemble high Antarctic landscapes than anything else in North America. As the ice flows to lower elevations, topography sufficiently constrains its source glaciers to valleys. But the Malaspina faces no such barrier as it flows beyond the mountains onto a coastal plain at the edge of the Pacific. Free of the restricting mountain topography, Malaspina deforms outward like a fan of thick batter spilled onto a tabletop. During the Iliamna Stade, circa 30,000 years ago, Naknek glacier looked much the same, flowing from roots in the mountains to a bulbous terminus at the edge of the lowlands. No glacial advance since has been as extensive or influential to Katmai’s geography, ecology, and history.
The Naknek glacier’s size, extent, and erosive power allowed it to accumulate huge amounts of till near its terminus. Much of its eroded debris was trapped within the ice and carried forward. Lesser amounts were pushed ahead as the glacier acted like an indiscriminate bulldozer. When the ice stagnated or receded, the reworked earth was dropped in place creating a terminal moraine, the ridge of till at the farthest reach of the glacier’s snout.
The glaciers of the Iliamna stade, especially the Naknek, thoroughly shaped the modern-day lake basins surrounding Brooks River. Its maximum advance is clearly inscribed on the land by the terminal moraine that now dams Naknek Lake. From the air this moraine, known locally as Pike Ridge, looks like a bore tide of earth flowing toward Bristol Bay. The moraine’s surface is uneven, hummocky, and pockmarked by kettle lakes. Vegetation covers most of it, hiding the raw frigidness of its formative time, but debris of all sizes, everything from clay and sand to car-sized boulders dot its surface. The moraine’s breadth—it spoons the western edge of Naknek Lake for 19 miles north to south—reveals how massive the glacier was as it greatest extent.
Near the end of the Pleistocene a warming climate never allowed the Naknek glacier to flow as far the Pike Ridge moraine. Each subsequent re-advance was eventually met by warmer and warmer conditions. The erosive and depositional influences of glaciers were waning even as the ice continued to leave its mark.
Between 23,000 and 10,000 years ago, several younger advances plowed through the same basins as the Naknek. While they failed to advance as far as the Iliamna stade, these smaller valley-filling glaciers were not inconsequential. They reworked previously deposited till, eroded bedrock further, and formed large moraines that are still visible. The North Arm of Naknek Lake and the west end of Lake Brooks are constrained by moraines from one such re-advance, the Newhalen Stade. Twenty thousand years ago, a last major resurgence pushed ice though Iliuk Arm toward Dumpling Mountain and the future site of Brooks River, halting only two miles from the present day river mouth.
The Iliuk was the last great stade in Katmai, and its moraine is one of the most prominent geologic features within my line of sight. Iliuk Arm, Naknek Lake’s southeastern-most appendage, sits on its far side. Water from Iliuk Arm flows into greater Naknek Lake through a breach in the moraine, a break which creates fingers of land reaching toward each other like the outstretched arms in Michelangelo’s Creation of Adam.
The slopes of Mount La Gorce and Katolinat dip steeply behind Iliuk moraine where the lake plunges to great depths. Unlike Naknek Lake’s western basin where glaciers were free to splay in broad lobes, the mountain topography on either side of Iliuk Arm restricted the outward flow of ice, but not its forward movement or erosive power. The topographical pinch enhanced and accelerated downward erosion in Iliuk Arm, over-deepening it. While the far western basin of Naknek Lake is often a mere 30 feet deep or less, the abyss of Iliuk Arm is at least 580 feet deep. With Naknek Lake’s surface averaging about 30 feet, Iliuk Arm reaches at least 550 feet below sea level.
All of these events have come and gone. Glaciers no longer spill into Iliuk Arm or threaten to overrun the overlook where I sit. No glacier has even advanced within 16 miles of the Iliuk moraine after it formed. Since then, Katmai’s glaciers have retreated to the crest of the Aleutian Range where volcanoes like Mount Mageik still harbor the right climate for their formation. Katmai’s glaciers are remnants of their former selves, yet I need not search long to see evidence that they still work the mountains. Through binoculars I spy Naknek Lake’s largest tributaries at the far end of Iliuk Arm, Savonoski and Ukak rivers. These rivers collectively drain much of central Katmai and each carry astounding loads of sediment eroded by glaciers on the Aleutian Range volcanoes.
I first canoed Savonoski River after paddling for two tranquil days on Lake Grosvenor, a crystal clear lake fed only by springs, unclouded creeks, rain, and snow. My canoe partner and I paddled casually to Grosvenor’s outlet stream. Conditions were placid and there wasn’t much of a need to rush. We relaxed at Grosvenor’s outlet as the flow pulled us downstream. After an hour of easy paddling, our trance was broken when we saw the outlet merge with Savonoski River. It was the antithesis of Grosvenor’s calm.
Savonoski was murky, swift, braided, and shockingly cold. There was no reliable way to judge any one channel’s depth from a distance. The water was so turbid that my fingertips disappeared from view mere inches below the surface. The river didn’t just look thick. It sounded thick, hissing with fine rock that sang off of the bottom of the aluminum canoe. We watched whole spruce trees tumble in the muddy water and carefully avoided others sweeping perpendicularly into the current. Near Naknek Lake, the river spread wide at its confluence with Ukak. On this delta, Iliuk Arm looked like a fjord on a stormy coastline.
Savonoski’s characteristics—icy water, braided channels, and the heavy sediment load—mark it as a classic glacially fed river. Its water pours out of the Hook and Serpent Tongue glaciers, which incessantly grind down some of the tallest volcanoes in Katmai. Much of the river’s larger sediments never arrive in Iliuk Arm, having been dropped anywhere the river’s energy is too weak to carry them further, but the glaciers mill some rock so finely it becomes microscopic, clay-sized bits called rock flour.
The name is apt. Rock flour has the size and texture of the finest white bread flour, ranging from 1 – 100 microns (a micron or micrometer is one millionth of a meter). The biggest rock flour particles, generally larger than 40 microns, are temporary inhabitants of the water column. They remain suspended if the water is continuously disturbed; such is the case in the fast moving Savonoski River where the water resembles a pale gray milk, but the bigger particles tend to sink quickly after reaching the calmer lake. The smallest rock flour particles, however, have a tendency to repel one another, not flocculate, which would cause them clump to sink faster. They are so small that friction in the water column allows them to remain in suspension for months even though they are insoluble. This makes the lake water in Iliuk Arm and near the mouth of Brooks River colloidal, a mix of microscopic insoluble particles (like rock flour) suspended in a second substance (like water). While many lakes in northern latitudes are exceptionally clear (visibility in nearby Lake Brooks extends dozens of feet into the water column) Iliuk Arm holds so much rock flour that visibility is often less than three feet many miles from the Savonoski.
Rock flour’s physical and chemical characteristics lend a deep vibrancy to Iliuk Arm. Naknek Lake shimmers opaquely, but not the pewter tone of lakes under overcasts skies. Instead it’s a garish turquoise blue. Suspended in the water column, rock flour scatters blue and green wavelengths of light exceptionally well creating the rich hues that meets my eyes. Drifting on Iliuk Arm in a kayak on a calm sunny day, surrounded by blue above and enveloped by turquoise underneath, looks and feels like paddling in sky.
Iliuk Arm and other glacially fed lakes owe their alluring look to the microscopically ground rock, but in many ways this is the least of the changes wrought by glaciers. Katmai and the Brooks River area were profoundly changed by ice. Almost every surface feature I see from the overlook has felt the effects. Glaciers repeatedly scoured the land and enveloped it for thousands of years. They ground much of the mountains to powder and moved a lot of the rest nearly to the Bering Sea. Without glaciers, the history and ecology of Brooks River and the entire region would be profoundly different. Yet this is a landscape that continues to evolve. Glaciers only sculpted the stage.
References and Notes:
Aleutian Low and atmospheric ability to hold moisture: Shulski, M. and G. Wendler. 2007. The Climate of Alaska. University of Alaska Press. Pg. 59, 96-99.
Precipitation models for Alaska: PRISM Climate Group. Oregon State University. http://prism.oregonstate.edu. Created 7 Feb 2017.
Many thousands of years ago precipitation patterns were very similar across southwest Alaska: Hults, C. P. and J. Fierstein. 2016. Katmai National Park and Preserve and Alagnak Wild River: Geologic Resources Inventory report. Natural Resource Report NPS/NRSS/GRD/NRR—2016/1314. National Park Service, Fort Collins, Colorado. Pg. 41.
Global temperatures were as much as 10˚C colder than today: Petit, J. R., et al. 1999. Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature 399 (6735): 429–436.
Glaciers trapped so much of Earth’s water to lower sea levels 125 meters: US Geological Survey. “Glaciers and Sea Level.” https://www2.usgs.gov/climate_landuse/glaciers/glaciers_sea_level.asp. Accessed 14 Feb 2017.
Ice movement and glacial coverage on the Alaska Peninsula: Mann, D. H., and D. M. Peteet. 1994. Extent and Timing of the Last Glacial Maximum in Southwest Alaska. Quaternary Research 42: 136-148.
Newly fallen snow is ninety percent air: Collier, M. 2004. Sculpted by Ice: Glaciers and the Alaska Landscape. Alaska Geographic Association. Pg. 66.
Information on the properties of glacier ice, formation, deformation, and movement: Hambrey, M. and Jurg, A. 2004. Glaciers, 2nd Edition. Cambridge University Press.
Cavities at the base of glaciers have been measured to contract and seal as fast as 25 centimeters per day: Lefeuvre, J. and Lappegard, H. 2015. Interannual Variability of Glacial Basal Pressure from a Twenty Year Record. Annals of Glaciology. V. 56. No. 70.
Ages of glacial stades in Katmai: Hults, C. P. and J. Fierstein. 2016. Katmai National Park and Preserve and Alagnak Wild River: Geologic Resources Inventory report. Natural Resource Report NPS/NRSS/GRD/NRR—2016/1314. National Park Service, Fort Collins, Colorado.
Fifty percent of AK Peninsula is glacially derived, Aleutian Islands would begin a scant 300 kilometers from Brooks River: Detterman, R. L. 1986. Glaciation of the Alaska Peninsula. Pg. 151–170 in T. D. Hamilton, K. M. Reed, and R. M. Thorson, editors. Glaciation in Alaska: The geologic record. Alaska Geological Society, Anchorage, Alaska.
The best modern analogs for the shape and behavior of the ancient Naknek glacier may be Malaspina and Bering glaciers: I was first introduced to this comparison in Reihle, J. 2002. The Geology of Katmai National Park and Preserve. Publication Consultants.
Malaspina Glacier shape and behavior: NASA Earth Observatory. 2015. Malaspina Glacier, Alaska. http://earthobservatory.nasa.gov/IOTD/view.php?id=86767. Accessed 7 Feb 2017.
Depth of Naknek Lake basins including Iliuk Arm: The exact depth of Naknek Lake is unknown. The estimates are based on sonar readings on boats in Naknek Lake; personal communications with Troy Hamon, Katmai’s Chief of Cultural and Natural Resources; and an unpublished lake bathymetry map provided by Chad Hults, geologist with the National Park Service, Alaska Regional Office.
- Ben, D. I. 2009. Glacial Sediments, Pg. 382 inV. Gornitz, editor. Encyclopedia of Paleoclimatology and Ancient Environments. Springer.
- Nichols, G. 2009. Sedimentology and Stratigraphy, 2nd Edition. Wiley-Blackwell. Pg. 107.
- Martha, G. 2016. Why are Lakes and Rivers in the Canadian Rocky Mountains so Brilliantly Turquoise Blue? http://sciexplorer.blogspot.com/2016/01/why-are-lakes-and-rivers-in-canadian.html. Accessed 8 Feb 2017.
- Love, H. 2012. What is Rock Flour? http://indianapublicmedia.org/amomentofscience/rock-flour/. Accessed 7 Feb 2017.
Friction in the water column allows [rock flour] to remain in suspension for months: As far as I know, this has not been empirically tested. However, Iliuk Arm retains its vibrant, turquoise hue even in winter when Savonoski River runs clear and flow out of Ukak River is at a bare minimum.
Visibility in Lake Brooks and Iliuk Arm: Moore, C. and J. Shearer. 2011. Water quality and Surface Hydrology of Freshwater Flow Systems in Southwest Alaska: 2010 Annual Summary Report. Natural Resource Technical Report NPS/SWAN/NRTR—2011/428. National Park Service, Fort Collins, Colorado.