Page "Avalanche" Paragraph 15

Slab avalanches, which account for around 90 % of avalanche-related fatalities, form when the application of dynamic forces causes catastrophic structural failure inside a weakness below a slab of snow.

Energy for fracture propagation is provided by gravity as the slab falls onto the weak layer.

This cascade of failures causes one layer of snow to delaminate from the layer of snow below, enabling gravity to pull the delaminated slab downhill.

Fracture propagation can be widespread, sometimes traveling for hundreds of meters, and in some cases kilometers, and can involve snow depths ranging from 10 centimeters to five or six metres.

Avalanches that form when the failure occurs between the base of the snowpack and the ground are known as full depth slab avalanches.