Avalanche awareness is critical for anyone traveling in snow-covered mountainous terrain. Understanding the types of avalanches, the conditions that cause them, and proper precautions can be lifesaving.
Start at a single point and fan out as they descend, creating a triangular shape. Usually smaller and less dangerous than slab avalanches, but they can still be deadly, especially if they carry a person over a cliff or into an obstacle.
The most dangerous type. A cohesive layer of snow fractures and slides as a unit on top of a weaker layer beneath. Slab avalanches can be triggered by the weight of a single person and involve enormous volumes of snow moving at high speed.
Avalanches require three key ingredients:
Terrain — Slopes between 25° and 60° are most prone (with 35°–45° being the danger zone). Convex slopes are more dangerous than concave. Open slopes without anchors (trees, rocks) are higher risk.
Snowpack — Layers of different density and bonding within the snowpack. Weak layers (hoar frost, faceted crystals, depth hoar) beneath stronger layers create the conditions for slab release.
Trigger — Additional weight (a person, new snowfall), temperature changes (rapid warming), wind loading, or vibration.
Check avalanche forecasts before heading into the backcountry. Learn to read terrain — avoid steep open slopes, cornices, and gullies. Travel one at a time across suspect slopes. Keep visual contact with each other. Watch for warning signs: recent avalanche activity, "whumpfing" sounds, shooting cracks in the snow, and heavy recent snowfall or wind loading.
Try to move to the side of the flow. If swept off your feet, try to "swim" to stay near the surface. As the avalanche slows, create an air space in front of your face. Try to push a hand toward the surface.