Avalanche: Snowpack Failure Dynamics (3D)

A slab of dense snow rests on a buried weak layer over a rocky substrate. The weak layer is modelled as a grid of cells, each with its own shear strength — reduced where a steep temperature gradient has promoted faceting — competing against the driving shear stress from the slab's own weight, ρ·g·h·sinθ·cosθ. Push the slope angle, slab thickness or temperature gradient far enough, or click the slab to plant a skier's load, and the weakest cell fails first; its neighbours inherit extra stress and the fracture propagates across the weak layer until enough of the slope has let go for the slab to release and slide.