Avalanche: Snowpack Failure Dynamics (2D) — Weak-Layer Bond Chain Cross-Section

Snowpack cross-section

Slope angle θ 35°

Slab thickness h 0.60 m

Weak-layer strength 1400

Temperature gradient 8 °C/m

Live Readouts

Driving stress τ

0 Pa

Weakest bond margin

Crack length

Status

Stable

Effective weak-layer strength (after faceting)

1400

How it works

The weak layer is a chain of ~60 discrete bonds running the length of the slope. Each bond has a shear strength set by the slider, weakened where a steep temperature gradient promotes faceting, and varying a little from bond to bond like a real, heterogeneous buried layer.

τ_drive = ρ·g·h·sinθ·cosθ
τ_bond(i) = strength · (1 − facet(∇T)) · (1 − 0.2·noise_i)
local stress(i) = τ_drive + skier load(i) + tip factor·(broken neighbour)

A bond fails once the local shear at its position exceeds its own strength. A broken bond raises the stress on its immediate neighbour — the same stress-concentration effect at a real crack tip — so once one bond snaps, the fracture tends to propagate outward along the chain rather than jumping to a random spot. When the crack spans enough of the slope, the block of slab between the crack tips separates and slides, accelerating under a = g(sinθ − μcosθ) until it reaches the flat runout, where friction alone decelerates it.

Click anywhere along the slab to plant a skier — a localized load concentrated on the nearest bond, often enough to nucleate the first failure.
Drag to pan the cross-section, scroll to zoom.

Click the slab to drop a skier load · drag to pan · scroll to zoom