Avalanche: Snowpack Failure Dynamics (2D)

This cross-section reduces the weak layer to a one-dimensional chain of bonds running down the slope. Each bond's shear strength competes against the driving stress from the slab's own weight, ρ·g·h·sinθ·cosθ, weakened further wherever a steep temperature gradient favours faceted, poorly-bonded crystals. A single failed bond concentrates stress on its neighbour, so a crack nucleated at the weakest point — or wherever you plant a skier's load — tends to propagate outward link by link until the freed span of slab breaks away and slides downhill.