Isn't it annoying that garden/fields seem to grow stones.
I wonder is it maybe http://en.wikipedia.org/wiki/Brazil_nut_effect
Cool. I want a jar of beetles, sand and pebbles on my desk too!
"Avalanches are gravitational granular flows,"
"When the avalanche flows over a terrain feature (steeper slope or surface irregularities), the flow can become turbulent (mixing) causing the victim to be pushed down. As the flow smoothes out, it is the particles segregating (de-mixing) that force the person back to surface."
"When an avalanche slows (but before it stops), the snow fragments interlock, resulting in a
change in state from a fluid-like flow to that of a sliding block (everything moves as a single unit or block)."
So. Esentially. Keep arms near face somehow.