Skiing on Mars
by Peter Shelton
May 27, 2010 | 4006 views | 0 0 comments | 32 32 recommendations | email to a friend | print
Glacier, permanent snowfield, semi-permanent snowfield? Summer turns by any name are sweet. (Photo by Bob Chamberlain; skier Peter Shelton)
Glacier, permanent snowfield, semi-permanent snowfield? Summer turns by any name are sweet. (Photo by Bob Chamberlain; skier Peter Shelton)
More summer skiing high above Trout Lake. Twenty thousand years ago all but the highest summits of the San Juans were covered by an ice cap. (Photo by Bill Ellzey)
More summer skiing high above Trout Lake. Twenty thousand years ago all but the highest summits of the San Juans were covered by an ice cap. (Photo by Bill Ellzey)
There is a black-and-white photograph hanging on my wall. It surprises me every time I look at it.

The top half of the image shows a roiling summer cumulus cloud rising behind a mountain saddle. The low belly of the saddle (connecting Sheep Mountain and San Miguel Peak) holds a remnant snow cornice. Below the cornice sun-cupped August snow is melting imperceptibly at the margins, pulling back from the rocks the way a wave retreats down the sand. In the middle of the retreating wave is a tiny figure bent into the comma of a ski turn.

Old friend and photographer Bob Chamberlain was visiting that summer. (It was sometime in the late 1970s; Chamberlain signed the photo but didn’t date it.) I had a personal goal that year to ski in every calendar month and asked if he’d like to join me on a hike to the Mars Basin snowfield. He said sure, and off we went one early dawn on the Hope Lake trail, ski poles in gloveless hands, skis and boots lashed to our daypacks.

In those days the high San Juans contained quite a few of what I considered to be permanent snowfields and what some geologists still insist are actual glaciers. None of them would remind you of Alaskan ice-rivers. They are small, thick pockets of snow that linger year to year. Whatever you call them (GlaciersOnline calls them “permanent snow and ice bodies”), there are 135 of them in the state of Colorado. The biggest concentration – 14 named glaciers – hangs out in shady nooks of the Front Rage around Rocky Mountain National Park. There are only four listed in the San Juans, none with names, all four on the alpine flanks of 14,245-foot Mount Wilson and its neighbor Gladstone Peak (13,914 feet).

I considered the north-facing snowfield in Mars Basin to be permanent. (There is no such designation on the map; I made up the name for the basin’s treeless sweep of Martian-red rock.) Other stubborn snow patches in the region seemed, with some annual fluctuation, to be permanent as well: Sheep Chute east of Lizard Head Pass, shards in the Sneffels Range and in Ice Lake Basin, thick wind and avalanche deposition in Savage Basin above Telluride where the Lunar Cup Fourth-of-July ski races have traditionally been held.

Glacier, permanent snowfield, semi-permanent snowfield – they have been shrinking in size and number, as one would expect in our warming climate. Still, on any given day in July or August, with a little imagination (you may not be able to see them from the main roads) and a bit of effort (they will be high on the peaks), it is possible to find skiable snow. And well worth the unusual notion of inviting your skis and boots along for a mid-summer hike.

Chamberlain and I veered off the trail after a couple of miles and scrambled up the steep, wooded approach to my hanging valley. Once over the lip, at about 11,600 feet, we were surrounded by soaring, glacier-carved walls on three sides. So-called valley glaciers (and their tributaries) were the main sculptors of this topography. You see evidence everywhere. In the broad U-shape of Bear Creek, for instance, where an ice river as much as 1,000 feet thick flowed north, then turned left to join Telluride’s bigger valley glacier sometime between 30,000 and 20,000 years ago.

The basic gouged U-form (as opposed to a river-carved V-shape) can be seen in the Animas Valley above Durango, in the three forks of Cimarron Creek (like parallel baguette pans dropping north out of the Big Blue Wilderness), and most obviously, thanks to Highway 550, in the Uncompahgre River Valley between Ridgway and Ouray. Those big sage-covered piles of outwash gravel downstream of Ridgway where Rusty Weaver built his pink Earthship house – those are the glacier’s terminal moraine, its bulldozer snout, the point where, at the last glacial maximum, the ice began its retreat.

Wooly mammoths may be long gone, but it’s wrong to refer to them as inhabiting “the last ice age.” We’re still in the last ice age, defined by “ice sheets cover[ing] large parts of Earth, such as Antarctica and Greenland.” And the Himalayan crest, and the Alaska Range, etc., etc. Sixty-nine point six percent of all the fresh water on the planet is locked up in ice. So, we’re living in an ice age. We may be warming our way out of it, but we don’t know when this million-year-old ice era will end.

We can talk about “the last glacial period” – the last time local glaciers were advancing, which ended about 12,500 years ago. And we can talk about “the last glacial maximum” – on the evidence of which Mr. Weaver’s moraine house sits. At that time, about 20,000 years ago, virtually all of the San Juans, from Chama to Rico to Creede, was covered in an ice cap. All but the very tallest peaks were submerged. The weight of that much ice grinding slowly downhill was an astonishingly efficient cutting tool. Mars Basin’s horseshoe-shaped cirque was scooped out as if by a giant trowel.

Chamberlain and I walked up the floor of the basin toward the snowfield. It was still a long ways away. It looked like a snow-white shirtfront between the lapels of an ochre dinner jacket. Rock in plate-sized fragments clattered beneath our boots. More rock fell from the walls on either side. We rarely saw movement, but we could hear the stony gargling. This is quick-time erosion, observable because the San Juans are so young and so steep. If, as some scientists say, the range is still growing upward, it is also falling down at an accelerated pace – geology in action, before your eyes and ears.

Only here and there did we see tiny islands of green free of recent rockfall, where soil turned up by pocket gophers supported mini tundra gardens: pink and yellow fairy slipper; moss pink and other miniature cushion plants; and at the melting edges of snow banks, the lily-pad leaves and sunny-side-up white flowers of marsh marigolds. One of the most ancient native plants, they have survived numerous glaciations.

The rocks here are more red-orange than they are the brilliant scarlet you see on Red Mountain Pass. But the color comes from the same source. Back before the glaciers, way back 26-30 million years ago, the range experienced its last (perhaps we should say its most recent) explosive volcanic upheaval, when much of the material we see today was deposited. Soon after, in geologic time, the calderas cooled and fractured. And into these cracks crept hot mineral solutions from below, including iron solutions, which oxidized and turned the rock red. Other mineral solutions worked their way up from the underlying mantle into the fracture zones, eventually to become veins of gold, silver, copper, lead and zinc.

I can’t be sure now, because I haven’t been back to Mars Basin for years, but as we approached the snowfield, Chamberlain and I may have been clambering over another kind of glacier – a rock glacier. These were unknown to science before they were first described by surveyors working in the San Juans in the 1880s. There is still some mystery surrounding their creation. But what is accepted is that there are more of them in the San Juans – 756 according to a 1984 survey – than anywhere else in the world.

On the surface, a rock glacier looks like an unusual landslide. In fact, that’s what the first observers thought they were. But the debris is strangely shaped, formed into ropy tongues, lumped in concentric circles like a nest of giant saucers. As Mel Griffiths put it in his wonderful book San Juan Country, it looks as if “molasses. . . was poured out on the slope from a gargantuan narrow-necked jug on a cold day.”

It turns out rock glaciers have an ice core, or an ice-matrix core, inside. This was discovered when a tunnel in Hurricane Basin, between Ouray and Lake City, was driven through the base of a rock glacier, and the miners encountered 300 feet of ice-choked debris. So, rock glaciers may be stagnant, still-frozen remnants of the last glacial period, or they may be exoskeletons of defunct glaciers, rockfall once carried on a glacier’s back now collapsed to the floor of a cirque.

Walking on snow at last, Chamberlain and I breathed the surprisingly cool air, like pure oxygen, pooled above the grainy surface. The snow grew steeper and steeper until nearing the saddle we had to kick steps to keep our balance. At last we hauled up on the cornice at 13,300 feet. Like a lot of glaciated features, our headwall ended in a knife-edge ridge with a mirror-image cirque falling away on the other side. Ours fed the San Miguel River. The one behind plunged into the headwaters of the Dolores.

We didn’t have a lot of time. Clouds were building already on the Dolores side, to darken perhaps and become thunderstorms later that afternoon. But we did sit for a while. We had the skiing to look forward to: 30 or 40 high-speed turns in shirtsleeves on sun-scalloped but pliable and possibly quite ancient snow. And it may sound strange, but it was also good to sit still and feel small.

We felt small physically, with the deep green canyons at our feet and peaks hundreds of feet higher still on either side. Small, too, in time: Our puny human life spans, however full of consciousness and marvelous acquired knowledge, were just an asterisk in the big story of rock and ice still unfolding all around.
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