Enjoying the backcountry in winter offers both unique recreational experience and cold-weather, life-threatening environments. Hypothermia, Frostbite and Cold Water Immersion/Thin Ice are perhaps the most common conditions regardless of locations across the wintry landscape. There are, however, several other potentially fatal ice/snow scenarios that, while more geographic specific based on the topography of the land, should be of a cautionary concern to winter adventurers as well.
Here are several snow/ice factor situations that demand caution by trekkers venturing across a snow-covered landscape:
- Post holing – breaking through a crusty snow surface, plunging your foot and leg deep into snow. This may not be life-threatening but can be very exhausting and cause you to tire. A thick crust could rip leg gear and cause abrasions on your skin. It could also impede you from reaching a safe haven from an approaching storm;
- Avalanches – Mostly in mountainous terrain but also prevalent on elevated, snow-loaded slopes between 30°- 45°. Suffocating avalanches can be triggered by the fracturing of an over-hanging cornice (see below);
- Cornices – an overhanging ledge of snow extending horizontally beyond a ridge or cliff rim, with the appearance of a frozen ocean wave. The cornice can fracture and collapse at various fracture points (edge of the rim, rock/tree at critical stress point/weight of additional snow). The resulting mass of collapsed snow can generate an avalanche or be large enough on its own to bury someone below.
- Snow Bridges – Similar to a cornice in that blowing snow forms a span over a crevasse, gulley, small creek channel – appearing solid but actually arching over a cavity beneath the surface. Falling into a deep opening, hard surface or into deep/swift-running water can occur when a snow bridge collapses under a snow trekker.
- Snow Immersion Suffocation – Falling face down into deep snow, particularly into a tree well (depression around the base of a coniferous tree as snow builds up beyond the branches). The partially inverted position of a victim wearing equipment on their feet (skis, snowboard, snowshoes) may cause one to become immobilized and find it impossible to right ones self after tumbling headfirst into such depressions – resulting in suffocation. In hazard research experiments, 90% of the victims could not rescue themselves.
- Glissading – Even the exhilaration of sliding down a slope for the sheer joy of it can be life-threatening if one’s speed or direction is compromised.
Both mountaineering and flat-land environments can pose serious threats to one’s safety in winter. Always check routes through snow for safety risks and threat and consider alternate routing. Snow cover can be quite deceiving and remember, ice is never 100 safe!