Avalanche

An avalanche occurs when a layer of snow loses its grip on a slope and slides downhill. The typical avalanche season begins in November, continuing into early summer for all mountainous areas. In the high alpine regions of the state, primarily in the Cascades and Olympics, avalanches are a year-round event.

Between 1960 and 2017, Washington experienced 129 avalanche events resulting in property losses worth $2.7 million. The counties of King, Pierce, Lewis and Whatcom experience the most avalanches, largely due to the terrain in these counties, including multiple skiing destinations.

In North America, avalanche accidents primarily involve winter sports enthusiasts, with at least 90% of avalanches that involve injury or death being triggered by recreational activity.

Avalanches cause roughly two fatalities per year in Washington although many more are involved in avalanche accidents that do not result in fatalities, but still cause serious injuries.  

Tips and Information about Avalanches

• Avalanche Forecasts 

• Northwest Avalanche Accident Summaries

• Northwest Avalanche Center (nwac.us)

• WA EMD Avalanche Threat Assessment - 2023 Data (PDF)

• WA EMD Avalanche Threat Assessment - 2013 Data (PDF)

• Disaster Preparedness Guide (PDF)

• WSDOT: Avalanche Control 

• American Avalanche Association

• Washington Trails Association