Windslabben

Windslabben is a term used in snow science, particularly in Scandinavian avalanche forecasting, to describe a wind-deposited slab of snow. It forms when wind transports loose surface snow and deposits it on lee slopes, building a cohesive layer that overlies a weaker snowpack, such as faceted crystals or a crust. The resulting slab—often simply called a wind slab—can vary in thickness from several centimeters to well over a meter, depending on storm strength, wind duration, and terrain.

Because the slab sits on a weak base, it can remain hidden until additional loading, such as a new snowfall, a skier or snowboarder crossing the slope, or a cornice failure, triggers a release. Stability is influenced by factors including slope angle (most avalanches occur on slopes roughly 30–45 degrees), aspect, wind direction, temperature, and the presence of moisture or surface hoar.

Detection and safety: Forecasters and backcountry travelers assess windslab risk by noting recent wind and snowfall, scanning for wind-loaded lee slopes, cornices, and cracking sounds. Snowpack tests and careful route planning help evaluate the strength of the interface between the slab and the weak layer. When windslab loading is active, avoidance of wind-loaded slopes, controlled tests if safe, and carrying avalanche rescue gear are standard precautions.

Origin of the term: The name reflects the wind-driven nature of the snow slab; in English this is commonly called a wind slab.