Extreme winds on Thursday and ongoing wind-loading on Friday will keep danger high in the alpine. Give all this new snow a couple days to settle before pushing out to bigger more committing terrain.
Weather Forecast
FRIDAY: Cloudy with a chance of sunny breaks followed by light snow 5-10 cm. The freezing level is around 1200-1400 m and winds are moderate from the south. SATURDAY: Periods of snow 20-30 cm. The freezing level is around 1200 m and winds are moderate gusting strong from the SE-SW. SUNDAY: Mainly cloudy with flurries. The freezing level hovers around 1200 m and winds ease to light.
Avalanche Summary
A widespread and large natural avalanche cycle probably occurred overnight Wednesday and on Thursday in response to rapid loading from snow and wind. All this new snow may take a couple days to settle and strengthen. Rider triggering remains likely on Friday, particularly in steep wind-loaded terrain.
Snowpack Summary
By Friday morning many areas could see as much as 100 cm of new snow on the ground. Weaknesses within or at the base of the new storm snow may need a couple days to settle and strengthen. Extreme southerly winds have created very deep and dense slabs in lee terrain, probably well below ridge crests, while scouring windward slopes. Ongoing stormy weather has also encouraged extensive cornice growth. The mid and lower snowpack are strong and well-settled.
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.