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  • Writer's pictureEd Sherline

Mammoth Glacier

Updated: Oct 10, 2022

Mammoth glacier and valley, Wind River Range, WY. Ed Sherline, 2022

Basics. Prior to receiving "Mammoth" as its legal name by the USGS, Meier tells us that this glacier enjoyed a few different monickers by climbers and geographers. "Wells Creek Glacier" because its outlet is the infamous Wells Creek, the most direct line to Gannett Peak's west gulley climbing route and a temptation to be resisted, with a notorious cleft, huge boulders, and the risk of a death fall (Kelsey, 100). "Green River Glacier" because it is the largest glacier sourcing the headwaters of the Green River. (Though Dale Lake is technically the ur-source of the Green, for my money, when you're standing on the terminal lip of Mammoth looking down and watching the water from its subglacial streams flow into daylight, you're watching the very beginnings of the Green.) "West Gannett Glacier" because, most evidently to those standing on the summit of Gannett, it is immediately west, so summiteers have a wonderful view of it, or its remains.

Mark F. Meier, Mammoth Glacier tongue from the summit of Gannett Peak, end of summer, from Glaciers of the Gannett Peak-Fremont Peak Area, Wyoming.

In size, Mammoth is the largest glacier on the west side of the Continental Divide, though only the third largest in the range, after Continental and Gannett glaciers. Guidebooks and those who study these glaciers like to repeat this ranking, as if its name requires mentioning its relative size. But to glaciologists who have travelled the world, Mammoth is a misnomer. It is a yawn, not even registering in the top fifteen non-polar glaciers. And for another "but," continuing to insist on ranking the size of the Winds' glaciers continues the pretense that all is well. Of course we can always measure and rank glaciers, even as they die, decay and disintegrate into disparate snow fields. Nonetheless, since these glaciers all suffer from the diagnosis of terminal melting, a ranking in the top three is less an honorific and more a grim observation: they have survived as living glaciers, glaciers that still have the dynamic of ice flow, of ingesting and churning snow and rocks, a little longer than their smaller kin.

In shape, Mammoth is a typical valley glacier downslope, with lateral ridges hemming the remaining ice on both sides. Up slope, it broadens into a semicircular and dish-shaped snow catching basin created by three of the Wind's tallest peaks: Mount Woodrow Wilson, Twins Peak, and Split Mountain.

The Power of Water. In these abnormally warm times, runoff from Mammoth is prominent--the noise from its white water rushing streams and Wells creek are deafening up close, sublime music of the valley.

"In a warming climate, increased glacier melt results in a component of runoff in excess of contemporary precipitation, termed the deglaciation discharge dividend. . . As deglaciation proceeds, the ice reservoir decreases in area and the amount of the dividend declines. The dividend vanishes when deglaciation is complete" (Benn and Evans, p. 85).

Since "deglaciation" (a chillingly scientific term) of Mammoth has continued at least since the 1930's (as noted by Meier in his 1951 study of it), the deglaciation discharge dividend is probably in decline, but you'd never know that when you're walking in its ever expanding, pervasively noisy outwash plain. The runoff begins with a few outlets where recent till piles permit the flow of water. Downstream in the sandier plain these outlets form a network of braided steams, with some lovely grass covered eyots (islands formed by these streams) in their midst. The end moraine abruptly pinches these streams together into the angry Wells Creek.

Mammoth valley sandur, Wind River Range, WY. Ed Sherline, 2022

"Most proglacial rivers carry large amounts of suspended sediment and bedload, and this is characteristically deposited in extensive, gently sloping outwash plains known by the Icelandic term sandar (singular: sandur). Narrow tracts of outwash hemmed in by valley sides in mountainous terrain are termed valley trains or valley sandar. The streams responsible for sandar and valley trains are typically braided due to a combination of steep gradients, abundant bedload, cohesionless bank and bed material, and fluctuating discharges" (Benn and Evans, p. 534).

Getting There. Meier noted: "The glacier can be reached from the Green River Lakes without too much difficulty." (Meier, 1951, p. 42). Probably the 23 year old he and the 62 year old I attach different senses to "difficulty." Once past the Green River Lakes, you must cross over the Green River and hike-scramble up Tourist Creek. The best cross-country guidebook to the Winds rates the curse-provoking Tourist Creek talus slopes to be "PG/R," which means travel is difficult--rough footing, complex micro route finding, steep elevation gain, super slippery in wet or snowy conditions--though a fall won't result in death (Pallister, 2017, p. 7). These days, since slipping on talus happens, PG/R is my non-negotiable ceiling.

The morning I was set to ascend Tourist Creek started with a special omen:

Moose in Three Forks Park, Wind River Range, WY. Ed Sherline, 2022.

As the two Moose ambled into my cooking area, I edged behind a climbable tree and proceeded to snap away with my phone camera. They mixed curiosity, checkin in with each other, and the morning business of eating. Their relaxed presence was an assertion of who this land really belongs to.

I reached the beautiful Scott Lake expecting to find people there, since it is the recommended base camp for those planning to climb Gannett by its west gulley. Arriving late in the day, I was greeted by a backpacker meticulously moving her tent around a patch of grass in a process like a shopper searching for the most comfortable mattress. When we shared our reasons for being in this remote spot, she planned to climb the west gulley the next morning. Though we were total strangers, I had to issue a warning (though with reluctance--I'm not comfortable in the role as wise elder, and didn't want to jinx her adventure). The west gulley route has a class 4 rating, meaning a "very exposed scramble," so that two climbers using a rope for belay is recommended in places to eliminate the risk of a lethal fall. Experienced climbers, including her, hear "class 4" as "casual solo." My warning was that this route should not be taken too casually; The year before a climber had tragically fallen on the decent. I don't know if this caution had any impact, but after successfully ascending the west gulley, she traversed Gannett's summit ridge and descended a different, less exposed, gulley system. I was hugely relieved to see her back in camp the morning after.

Deep in the Winds alone, I have a low grade nervousness that surfaces in a superstitious outlook, always looking for good omens. A beautiful morning sunrise provided one:

Scott Lake, Sunrise, Wind River Range, WY. Ed Sherline, 2022.

The Rephotos. I started with one of Meier's photos from the edge of the glacier valley opposite the ridge-line of the Continental Divide, and worked my way up this side. Here is the first of Meier's photos I pursued:

Mark F. Meier, Mammoth Glacier, 8/20/1950, retrieved from the website Glaciers of the American West. Retouched in Silver Efex Pro 2.

Here is my rephotographic effort:

Ed D. Sherline, Mammoth Glacier from the western lateral moraine, 8/10/2022.

And here is their juxtaposition:

Left: Meier, 1950; Right: Sherline, 2022

I was surprised to discover that Meier's vantage point is much higher than I originally guessed from his photo. Meier's point seems below the upper surface of the glacier, and that you're looking up glacier rather than across it. The supraglacial lake at the bottom of Meier's photo (a temporary lake on top of the glacier) has completely disappeared, and so the only benchmarks were the peaks and the bedrock bulge barely poking out of the glacier in Meier's photo. Based on the topo map elevations and the height of the bedrock bulge, the glacier has probably thinned around 300 feet!

While high on the ridge I spotted a tiny pond (11550) that is the vantage point of another of Meier's photos of Mammoth:

Mark F. Meier, Mammoth Glacier, 8/19/1950, retrieved from the website Glaciers of the American West. Retouched in Silver Efex Pro 2.

Here's what it looks like today:

Ed D. Sherline, Mammoth Glacier from Lake 11550, 8/10/22.

Geologically, "ice-marginal lake" is probably the most accurate technical name, to distinguish it from larger moraine-damned lakes. Glacier scouring created a depression in the bedrock. Meltwater filled it. Meier (1950, 41) notes the depression in the bedrock and the way the moraine curves around. The main reason this tiny lake has persisted here despite the massively shifting moraine around it is the anchor its bedrock depression provides.

Left: Meier, 1950; Right: Sherline, 2022.

Meier's vantage point and mine are at about the same elevation, but his is to the right. He found an angle to the background wall of mountains closer to 90 degrees, opening them up more. Moving further over wasn't available to me, since the moraine descending from the upper right corner has greatly increased in the intervening 70+ years. It would have obscured even more of the background mountains; there would have been no way to tell that the two photos are of the same lake.

In 1979 I had a chance to look down upon Mammoth glacier from the top of Twins Peak in an unforgettable "holy shit" moment.[1] I had never seen a glacier so large and up close. My high-school best friend and I were total novices as mountaineers, and the climb up was a terrifying no-way-we're-going-back-down-this. Until that fear subsided and better judgment prevailed, an uncontrolled slide down the glacier seemed the best way off the peak. Please do not misinterpret my telling this story as an attempt to generate any kind of heroic narrative. Not at all. Instead, I use it as an excuse to compare the conditions of the glacier then and now. In 1979, Mammoth still had a lovely firn basin; its upper reaches were covered in smooth snow. A glissade with the proper equipment wouldn't have been out of the question. Meier's photo from 1950 isn't far from what I remembered. I was probably looking down on the glacier from the very center of the photo, where the snow reaches up to the split between east and west Twins Peak.

Mark F. Meier, Mammoth Glacier, 8/20/1950, retrieved from the website Glaciers of the American West.

Now that I've been to the area, I realize that the vantage point for Meier's photo overlooks the lower portion of Split Mountain Pass (the snow ramp leading up the right corner). When on glacier I did not move up glacier far enough. Instead, fixated on finding boulders for the lower right corner of the image and a mountain edge to frame the right side (go figure?), I climbed into the col just before the pass. It was steep, wet, filled with heinously loose talus, and the upper portion was beginning to release large rocks due to melting ice. I hurriedly took this shot:

Ed D. Sherline, Mammoth Glacier from near Split Mountain, 8/10/22.

Left: Meier, 1950; Right: Sherline, 2022.

An apology: As both the rephotographer and writer, I seem to be devoting too much time to me, to discrepancies between Meier's and my vantage points, and not enough time on the glaciers, on the in-your-face changes and the more subtle implications. It is too easy to get caught up in obsessively writing about the most obvious in a rephotography project, how close the recent photos come to achieving the highest standard of exactly repeating the earlier photography, and why they don't when they don't. But when comparing the photos I tell myself, with varying degrees of self-credibility, that the exact repeat is only the highest standard if one is doing quantitative glaciological work, or attempting to make points about the nature of photography and how we view a photograph. I'm attempting to make highly graphic points about the changes in the glaciers, and that doesn't require exactitude.

On the last day in the area, I aimed to rephotograph this lovely shot of Meier's:

Mark F. Meier, Mammoth Glacier, 8/21/1950, from Glaciers of the Gannett Peak-Fremont Peak Area, Wyoming.

This is one of my favorites. The vantage point is dramatic, the view complex, and the variety of tones as well as the lovely smooth whites of the glacier produce a classic alpine image. This photo was the "must obtain" of the trip. Here is my rendering:

Ed D. Sherline, Mammoth Glacier from east ridge, 8/12/22.

Left: Meier, 1950; Right: Sherline, 2022.

Just move your eyes back and forth between the two images, and take in the most immediate difference: the massive shift of white enveloping snow to dark grey rock and dirty snow remnants. This is what climate change means in black and white.

Saying Good Bye. In 1950 Meier established that Mammoth glacier was receding due to natural warming after the Little Ice Age. Neither he, nor I in 1979, knew that there was an atmospheric change of global proportion developing out of sight just above us. We've now lived with that curtain fully drawn for over thirty years, though only recently have I turned the camera onto a small part of the ongoing reveal. It sometimes feels like this rephotography project is too late; especially too late to capture the beauty of the glaciers. But even as the glaciers dwindle, the beauty of the Winds persists. This isn't intended as a bromide. Nor is it intended to imply that the good outweighs the bad. Quite the contrary, the increasing distance between the beauty of the Winds and its disappearing glaciers makes the latter a more bitter pill to swallow. But it is undeniably comforting to realize that as places change, so too does what we find beautiful in them.

Mammoth Glacier Overlook, Wind River Range, WY. Ed Sherline, 2022


1. I'm not sure whether the mountain we climbed was Twins Peak or Split Mountain. My friend thinks it was the latter. In his favor, Split Mountain was closer to our camp at Peak Lake, and with a more direct approach. But we were using the Bonney guidebook, which rates Split Mountain's W face as 5th class, whereas Twins Peak's SW face is an easier class 4. Surely we would not have been so foolhardy as to have taken on a climb rated as requiring advanced climbing skills. And my memory of the view we had of Mammoth glacier seems to fit better with being on top of Twins than of Split Mountain. But older memories are unreliable, and maybe I'm giving our late teen selves too much credit.


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