Outdoor Safety & Ethics: Avalanche Safety

The aftermath of an avalancheAvalanches kill more people on national forests than any other natural hazard. The best way to stay safe is to know the conditions, get the training, carry rescue gear and stay out of harm's way. Avalanches come in many shapes and sizes and even small ones can be dangerous. In general, there are three types of avalanches: ​

Slab Avalanches:

Most people that die in avalanches, die in slab avalanches. Slab avalanches occur when a more cohesive or harder layer of snow sets on top of a less cohesive or softer and weaker layer of snow. Some times the weak layer can barely support the layers above it and when additional weight like a skier or boarder is added to the upper layers, the weak layer collapses and the snowpack fractures and a slab avalanche occurs.

Sluffs or Loose Snow Avalanches:

Sluffs are cold snow/powdery surface slides that typically are the least dangerous type of slide; however, sluffs can and often do injure skiers and boarders by pushing them over cliffs and rock bands in steep terrain. Sometimes you can ride next to them or through them but if they knock you over in the wrong spot they can definitely ruin your day.

Wet Avalanches:

Wet slides occur when warm temperatures melt the surface snow layers and saturate them with water. The water weakens the bonds between layers and avalanches often occur. Wet avalanches move more slowly than dry avalanches but they can still be very dangerous

Learning to recognize avalanche terrain is the first and most important step in avalanche hazard evaluation. Slopes less steep than about about 30 degrees are such a low angle that they rarely avalanche. However, slopes steeper than about 30 degrees and especially slopes steeper than about 35 degrees can and often do avalanche. And many of us like to ski and snowboard on slopes steeper than 30 degrees and that puts us in avalanche terrain...if it is exciting it is probably 35 degrees or steeper.

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