🏔️ Presets

Stable

Marginal

Primed (skier)

Natural release

Snowpack & slope

Slope angle: 38° Slab depth: 0.8 m Weak-layer strength: 1.0 kPa New-snow load: 0.0 m

Stats

Stability index—

Slope angle—

Slab mass—

Runout—

Size class—

Released?—

A cohesive slab rests on a buried weak layer. The driving shear stress is the slab weight component along the slope (∝ depth · density · sin θ); the resisting strength is the weak layer's shear strength. The stability index = strength ÷ stress. When a trigger — a skier, new snow, or warming — pushes the index below 1, the weak layer fractures, the crack propagates, and the slab releases and breaks into flowing granular debris. Slopes of 30–45° are the danger zone: steep enough to slide, not so steep that snow sloughs continuously.