Loose Wet
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Sunny conditions and mild temperatures will destabilize the snow surface as the day warms, making loose snow avalanches possible on steep slopes ranging from E-S-W. Humans may trigger these avalanches or they can release naturally near exposed rocks/cliff bands. They begin at a point and fan out to collect debris as they move downslope. They are commonly small but can really pack a punch in the wrong terrain or push a rider into consequential areas. These will primarily appear as wet loose avalanches; however, solar-induced dry-loose avalanches can also occur on shady slopes and remain as dry snow but essentially be triggered by the same mechanisms of a wet loose avalanche (i.e., solar input or human movement).
Watch for obvious signs that the warm sun is wetting the surface of the snow. Thinly covered rocks and cliffs are the first areas to shed. Small roller balls or pinwheels of moist snow can be an early warning that loose snow slides may follow. Pay attention to what's above you. You can largely avoid this problem by sticking to colder, shaded aspects or lower-angle terrain.
(3/9/2025)
Wet and dry loose snow avalanches spanning various aspects in the upper Greys.
Photo: Bridger-Teton Avalanche Center