Granular physics in action
Figure 3. A simulation of the particle dynamics of an avalanche shows what happens to a large white particle placed at the bottom of the flow. After several seconds, the particle migrates to the top of the flow in a process called "squeeze expulsion". Such simulations illustrate how an "air bag" could save the life of a skier caught in an avalanche by preventing him or her from being buried. They also provide important insights into avalanche flow.