Avalanche 11
Avalanche 11 : Natural Disaster. A mass of snow sliding, tumbling, or flowing down an inclined surface. Technically, a mass of loosened snow, ice, and/or earth suddenly and swiftly sliding down a mountain. In practice, assumed to be a snow avalanche unless another term such as ice, rock, mud, etc. is used. (Avalanche-center.org) (ISDR)