Triggering storm slabs is a concern at all elevations. Be very suspect around wind-affected slopes and convex terrain features.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
MONDAY: Clear and cold with moderate north wind and alpine high temperatures around -10 C.TUESDAY: Mostly sunny, light wind, alpine high temperatures around -10 C.WEDNESDAY: Mix of sun and cloud with isolated flurries, light wind, alpine high temperatures around -8 C.
Avalanche Summary
No new avalanches were reported on Sunday, but storm snow was very reactive on Saturday. Numerous size 1-2 slab avalanches were triggered by skiers on all aspects at treeline and below treeline, including some that were triggered remotely (from a distance).Looking ahead, avalanche activity is most likely in areas that have been loaded with the recent northerly winds, but any steep terrain feature is suspect given the widespread crust sitting beneath the storm snow.
Snowpack Summary
In sheltered terrain, cold weather is preserving 30-50 cm of low density snow. In exposed terrain, strong north winds have scoured north facing slopes and loaded south facing slopes. A hard rain crust that extends into alpine terrain is buried about 40 cm beneath the recent storm snow. Reports suggest the snow has not yet formed a strong bond to the crust, creating a potential bed surface for slab avalanches. Monitor the bond of the new snow to this crust closely in your local area. There are no significant layers of concern below the crust.
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.