Analytical study of powder snow avalanches

Abstract

Appropriate expressions describing the motion of powder snow avalanches are derived. The model consists of four equations, i.e. the conservation equations of air, snow particles, momentum of avalanches, and kinetic energy of turbulence. The total buoyancy of powder snow avalanches changes freely via erosion and deposition of bed material. In the model presented, the snow entrainment rate from bed is directly linked to the level of tubulence.
The rate of development of strongly accelerated avalanches is obtained with the aid of numerical integration. The model gives a good explanation of the characteristics of the powder snow avalanche, i.e. the quick formation of thick clouds and the very fast speed of the front. To the extent that observations exist, the prediction of powder snow avalanches obtained herein is in general agreement with those observations.