An avalanche is a large mass of snow, ice, and rock that slides down a mountainside. Avalanches are one of the most dangerous natural hazards in the world, and they can occur without warning.
The first recorded avalanche in North America occurred in 1721 in what is now western Canada. The event was so large that it buried an entire village and killed more than 60 people. Since then, there have been many other large and deadly avalanches in North America and around the world.
