The turbulent flow of avalanche debris suspended in the air.

Credit: Michael Bründl, Swiss Federal Institute for Snow and Avalanche Research

Flowing avalanches (typically dry) can cause a turbulent cloud of airborne snow particles.  Powder clouds can travel over 180 mph (300 km/hr) and cause significant damage extending beyond the runout of debris on the snow surface.  Larger slab avalanches and terrain with longer vertical relief tend to produce more destructive powder clouds.


Credit: Chugach National Forest Avalanche Information Center