The process of cohesionless snow moving downslope and entraining more snow (also called sluffing).

Credit: Crested Butte Avalanche Center

Given the pre-existing condition of loose surface snow on a steep slope, point releases gain momentum from a human trigger or are spurred by small changes at the surface such as warming or snowfall.  Point releases grow from grain to grain contact, similar to sand on a steep sand dune.  Point releases cause Dry Loose and Wet Loose avalanches. 

A point release in wet snow, causing a Wet Loose avalanche. Credit: Crested Butte Avalanche Center