Quick Answer
Factors that increase the chances of an avalanche triggering include steep terrain, recent snowfall, and wind-blown snow. These conditions can create unstable snow layers prone to sliding. The likelihood of an avalanche also increases with the weight of a person or group.
Terrain Factors
Terrain plays a significant role in avalanche formation. Steep slopes with angles greater than 30 degrees are more susceptible to avalanches. In particular, slopes with angles between 35 and 40 degrees are considered high-risk. The shape of the terrain also matters, with convex slopes and gullies being more prone to avalanches than concave slopes.
Snow Conditions
Recent snowfall and wind-blown snow increase the likelihood of an avalanche. New snow can create a weak layer on top of the existing snowpack, while wind-blown snow can transport loose snow and create a layer of unstable snow. The snowpack’s temperature, moisture content, and crystal structure also affect its stability. A temperature gradient of 5-10 degrees Celsius (9-18 degrees Fahrenheit) over a short distance can indicate a potential avalanche.
Human Factors
The weight of a person or group can trigger an avalanche, especially if they’re standing on a slope with unstable snow. A single person can weigh up to 90 kilograms (198 pounds), which is enough to initiate a slide on a steep slope. Additionally, the presence of multiple people or a group’s cumulative weight can increase the likelihood of an avalanche. In high-risk terrain, it’s essential to assess the snow conditions and terrain before traveling and to avoid standing on slopes with unstable snow.
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