Critical Loading

Raven Eye Photography

A sledder investigates a slab avalanche triggered when a critical amount of new snow overloaded a weaker layer.

Critical loading happens when new precipitation or windblown snow overloads a slab sitting on a weak layer. A slab that has reached its critical load may avalanche naturally or with a light trigger.

The suggested threshold for identifying critical loading is 30 cm or more of new snow, or significant wind, or rain during the 24-hour period prior to and up to the end of your day.