Avalanche Essentials by Bruce Tremper

Author:Bruce Tremper
Language: eng
Format: epub
Publisher: Mountaineers Books

Photo 4-4. When traveling, I probe with my ski pole hundreds of times a day to feel the unseen layers below. With harder snow, I turn my ski pole upside down. I often use my rescue probe to test layers and see the total depth of the snowpack. Avalanches are not mysterious or unpredictable, they are just invisible, hidden beneath the perfect façade.

Armpit Test

To test after a storm or for shallow weak layers, I do the armpit test dozens of times as I travel along. Dig out a small hole with your hand and then, on the uphill side, saw out a small square of snow with either your hand or the handle-end of a ski pole. Pull on this snow to see how well the surface slab is bonded to the underlying snow. See Photo 4-5.

Step Above the Track

You can do this test on skis, a snowboard, a snowmobile, or snowshoes. I occasionally step above the track and kick some surface snow onto the trail below. Or, climbing a slope on skis, at the apex of each switchback, I kick the snow and look for little slabs that pop out between the switchbacks.

Slope Cuts (aka Ski Cuts)

Ski cuts have been a standard technique among ski patrollers and helicopter ski guides for decades, but snowboarders and snowmobilers can do these tests as well, so instead I call them slope cuts. The idea is that if you might trigger an avalanche, you want to do it fully aware, with your speed built up, and heading for an island of safety. In theory, if the slope does fracture, your momentum will carry you off the moving slab, which helps minimize the chances of getting caught (see more details in Low-Risk Travel Rituals in Chapter 5).

Test Slopes

This is my favorite backcountry test. Find a small, steep slope where the consequences of a slide are small, such as a road cut or a small breakover in the slope. Look for something about 3–6 meters (10–20 feet) high. Then jump on the slope to see how it responds. If I get an avalanche on the test slope, I will definitely avoid any larger, more dangerous slopes with the same aspect and steepness. A test slope is a gift that you should never pass by without jumping on it (see Photo 4-6).

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