Confidence
Fair - Due to variable snowpack conditions
Weather Forecast
Friday: Light snowfall during the day intensifying to moderate in the late afternoon / Moderate to strong southwest winds / Freezing level at 1000mSaturday: Light snowfall / Light southwest winds / Freezing level at 1200mSunday: Possible sunny breaks / Light northeast winds / Freezing level at 1200m
Avalanche Summary
Avalanche observations have been limited in the last few days; however, 2 explosives controlled size 2.5 slab avalanches were reported from the Duffey Lake area. They occurred on a north facing alpine slope and ran 1000-1400m.
Snowpack Summary
Moderate to locally heavy amounts of snow fell on Wednesday. At lower elevations rain continued to saturate the snowpack. The storm was accompanied by moderate to strong south/southwest winds which left variable snow distribution in exposed areas near ridgetop with dense wind slabs forming in lee and cross-loaded features. Up to 75cm below the surface you will likely find a melt-freeze crust from last week's sunny weather. At the same interface, you may also find spotty surface hoar on some high, north facing slopes. Cornices are very large and could pop off with continued mild temperatures.
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.