Skintrack Observations (Definitely Not a Field Guide)

A skier’s look at the geology, wildlife, and hidden stories beneath your skins.

By John Smidlein
Policy Intern

June 24, 2026 – After moving to Truckee, I noticed new natural features on each of my tours this winter. It had me asking a lot of questions, and made me realize how much I could learn about the environments I spend my time in. So the first thing I did was dig into what I was seeing locally. It was pretty fun, so I decided to broaden my scope and look into defining features of key landscapes where WWA and our partners work. I tried to find interesting fun facts that could make your next tour a little more colorful. Hope you enjoy!

Lake Tahoe, California / Nevada

The smooth granite slabs you’re skinning by were shaped by glaciers more than a mile thick. The slow-moving ice left two things you can see today: striations, the long parallel scratches that show the direction it flowed, and glacial erratics, the random boulders sitting alone made of completely different rock from everything around them. They got picked up by the glacier and abandoned when it melted.

The orange and green patches on the rock outcroppings are lichen. Each one is two organisms living as a single unit, a fungus and an alga. They dissolve rock extraordinarily slowly, which is one of the main ways boulders eventually become soil.

Keep an eye out for Clark’s nutcrackers: jay-sized gray birds with black beaks that bury tens of thousands of pine seeds every fall and relocate most of them months later through several feet of snow. Researchers call it one of the most impressive spatial memories in the animal kingdom (Cornell Lab of Ornithology). The whitebark pine forest you’re skiing through largely exists because these birds missed a few of their caches. Mountain chickadees have their own trick. Each night, they deliberately lower their body temperature by up to 22°F to burn fewer calories, a process called torpor, and wake up fine in the morning (The Condor, 2005).

Lake Tahoe

Sawtooth National Forest

Sawtooth Range, Idaho

The Sawtooths got their skyline from glaciers eroding in from multiple directions at once. Where two glaciers pushed toward each other from opposite sides of a ridge, they left a thin serrated spine called an arête.

Many of the aspen stands on south-facing slopes aren’t separate trees at all but single organisms, one root system sending up hundreds of identical trunks. A group of these aspens is called a clone, and they can cover many acres and live for thousands of years. Look closely at older trunks and you may find arborglyphs, carved names, dates, and drawings left by Basque sheepherders in the late 1800s.

Near treeline, the low woody mats pressed flat against the ground are krummholz, German for “crooked wood.” These are full-grown Engelmann spruce trees, possibly 200 years old, shaped entirely by exposure to the elements. The gray jays work the same terrain, cache food all fall, nest in late February while buried in snow, and raise their chicks entirely on what they stashed months earlier (Cornell Lab of Ornithology).

Wolf Creek Pass & Red Mountain Pass, Colorado

The San Juan Mountains sit on one of the largest volcanic fields in North America, roughly 9,700 square miles of ancient caldera terrain (USGS). The red, rust, and ochre staining on the cliffs along Highway 550 is hydrothermal alteration: iron-rich hot water baked into the rock for millions of years. That same process deposited the silver ore that set off one of Colorado’s biggest mining booms in the 1880s. By 1893, when silver prices collapsed, the towns that had sprung up almost overnight were mostly gone. The headframes are still visible from the road, and the terrain above the pass sits over a honeycomb of old mine tunnels.

Wolf Creek averages 430 inches of snow a year, the most of any resort in Colorado (Wolf Creek Ski Area), due to a collision of Pacific and Gulf moisture. Under all that snowpack, in the subnivean zone between the snow and the ground, shrews and voles move around insulated from the cold above. The crisscrossing dirt tunnels you see in spring are the remnants. Above treeline, watch for white-tailed ptarmigan, practically invisible in winter until they move. With toe feathers grown out like snowshoes, they look like a confused white chicken standing on the snow.

Red Mountain Pass

Teton Range

Teton Range, Wyoming

The Tetons have no foothills because the range tilted instead of folding upward. The Teton Fault runs along the eastern base, and as it moves the mountains rise while the valley drops at a rate of roughly a foot every 300 years (Wyoming State Geological Survey). The dark, banded rock that looks like melted ice cream you find at the summits of Teton mountains is Precambrian gneiss, up to 2.875 billion years old and some of the oldest exposed rock on the continent (USGS).

Those smooth, contact lens-shaped clouds sitting motionless over the ridge are lenticular clouds. They look still from the valley, but air is screaming through them. They reliably mean serious wind at the summit.

The Tetons also have a specific place in skiing history. On June 15, 1971, an Exum guide named Bill Briggs climbed the Grand and made the first ski descent of the peak, a line most people had considered impossible. The descent was foundational in North American steep skiing. Teton Pass has been a backcountry corridor since the 1890s, and the Teton Backcountry Alliance estimates around 150,000 runs are skied there in a single winter (Visit Jackson Hole).

Mount Washington

White Mountains, New Hampshire

The White Mountains’ pale granite cooled about 160 million years ago, and all the rock that once sat above it has since eroded away completely. The notches were carved by a glacier over a mile thick, the same sheet that covered all of New England out to the continental shelf. The forest that looks old and dense is mostly 125-year-old regrowth, a response to the industrial logging that had stripped these mountains bare by 1900. The easy, flat trails cutting through otherwise rugged terrain, like the Zealand Valley, are old railroad grades. The stone walls buried deep in the woods once bordered open farm fields. When farming moved west after the Civil War, the forest grew back around them.

Mount Washington is a classic ski tour of the northeast and its weather is no joke. On April 12, 1934, the summit recorded a 231 mph wind gust, still the fastest surface wind ever directly observed by a human (Mount Washington Observatory). It averages over 100 days per year with hurricane-force winds.