Loose Wet
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
A decent but superficial snow surface refreeze is expected to have occurred last night with clear skies and air temperatures only a few degrees above freezing mid slope and on the peaks. As the day progresses, strong sunshine and warm weather will melt through the refrozen surface crust, exposing a deeper layer of wet snow. Wet loose avalanches will become possible as the surface refreeze crust melts away. Long steep slopes can produce larger wet snow avalanches. Smaller wet loose avalanches can have consequences in areas with downslope terrain hazards such as cliffs or creeks. The remaining large and overhung cornices that exist along some ridgelines will continue to melt, weaken, and possibly collapse.
Anticipate that snow surface conditions may change from firm and supportable to wet and mushy in a fairly short period of time today. Pay attention to the terrain and changes in conditions as you travel. Clues like sinking into boot-top deep wet snow, roller balls, a loss of supportability at the snow surface, and wet snow sluffs indicate that conditions are prime for backcountry travelers to trigger wet loose avalanches. Once the snow feels wet and mushy, it's time to exit avalanche terrain.
The snow surface will lose supportability as the crust formed overnight on the snow surface melts away. Once the crust melts enough to expose the residual wet snow below that does not refreeze overnight, larger wet loose avalanches are possible.
(4/17/2024) Open E aspect slope near 8,000' on Andesite Peak, Donner Summit, CA.
Photo: Sierra Avalanche Center