Definitions for "Avalanches"
Debris avalanches (volcanic landslides) are rapid downslope movements of rock, snow, and ice. Landslides range in size from small movements of loose debris on the surface of a volcano to massive failures of the entire summit or flanks of a volcano. Volcanic avalanches and landslides can occur even when the volcano is not erupting. Excessive rainfall and/or earthquakes may start the material moving down hill.