Slab avalanche

Slab avalanches (figure 5), which are generally much more dangerous to people and property than loose snow avalanches, involve the release of cohesive snow blocks through fractures and normally involve a large part of the depth of the snow cover. In fact, they are only possible when a layer of snow with a certain cohesion rest on a fragile layer, and when this stratification extends over a sufficiently large area. In addition, an overload is required to trigger the avalanche, and the slope must be inclined by at least 30°. They can be triggered spontaneously (without human intervention), or they can be triggered from any point on the fracture surface (by an alpinist for example), or even from outside (remote triggering). Slab avalanches are the most dangerous and account for more than 90% of all victims.