Jennifer Coulter

Slab forming above a weak layer of surface hoar.

A slab is one or more cohesive layers of snow overlying a comparatively weak snowpack layer. Slab formation takes place as low density new snow densifies and stiffens from the effects of settlement. Wind transport is another common contributor to slab formation. The presence of a slab over a weak layer is one of the preconditions for a slab avalanche.