The first hit of sunshine could trigger storm slabs and loose snow avalanches from steeper, alpine features.
Confidence
Moderate - Due to the number and quality of field observations
Weather Forecast
Friday: A mix of sun and cloud with treeline temperatures near -4 and freezing levels dropping to 400 m. Ridgetop winds light from the North.Saturday: Sunny. Treeline temperatures near -3 and freezing levels valley bottom. Light winds from the North.Sunday: Some cloud with light flurries. Treeline temperatures near -3 and freezing levels valley bottom.
Avalanche Summary
No new avalanche reports on Thursday.
Snowpack Summary
Rain over the past few days has saturated snow surfaces and only higher alpine elevations were lucky enough to get snow. With a forecast cooling trend, the upper snowpack will likely lock up as a firm crust. The average snowpack depth at treeline is 300 cm of well settled snow with no significant layers of concern.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.