Quick Answer
Avalanches can be triggered by a combination of factors, including recent snowfall, temperature fluctuations, steep slopes, and terrain features. Experienced mountaineers look for signs such as recent avalanche activity, cracking or collapsing snow, and sudden changes in snow texture. These indicators can signal a higher risk of avalanches.
Recognizing Avalanche Risks
When assessing avalanche risk, pay attention to recent snowfall amounts. In general, 12-18 inches (30-45 cm) of new snow in a short period can increase the risk of avalanches. This is especially true if the snow is heavy, wet, or has a high water content.
Reading Avalanche Terrain
Steep slopes are a primary concern when evaluating avalanche risk. Angles of 30-40 degrees (50-67 degrees in metric) or steeper are generally considered high-risk terrain. Additionally, look for features such as gullies, ridges, and bowls, which can funnel and amplify snowfall, increasing the likelihood of an avalanche.
Analyzing Snow Conditions
Changes in snow texture can be an important indicator of avalanche risk. Look for signs of recent slab formation, such as a layer of hard, smooth snow overlying softer, more cohesive snow. This can be a sign of instability and increased risk of an avalanche. Experienced mountaineers use tools like the “Avalanche Danger Scale” to assess snow conditions, with ratings from 1 (low) to 5 (extreme).
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