Snow Avalanches

Snow avalanches occur in many areas of Canada, mostly in remote or uninhabited locations. The few that impact society cause significant damage. Snow avalanches have killed over 570 people in Canada since the mid-1800s. Traffic delays and damage to forests cost millions of dollars annually. Slab avalanches cause most of the hazard to people, property, and infrastructure. They are released by a failure within a weak layer or at a weak interface underlying one or more layers of cohesive snow. Point-release avalanches start in relatively cohesionless snow and are usually smaller. Slope angle and orientation to wind strongly influence the formation of avalanches. Avalanche hazards to buildings and transportation corridors can be mitigated using structural methods. Ski areas and transportation corridors often require forecasting and control programs to reduce the avalanche hazard. About half the people buried in avalanches die within 30 minutes. Portable transceivers reduce search times and increase the odds of finding victims alive.