New snow and a widespread weak layer are increasing the avalanche hazard.
Weather Forecast
A series of storms continues to track across the area over the next several days. Expect light precipitation today with freezing levels around 1500m and moderate SW winds. A major storm front will arrive mid-morning Saturday. Up to 50mm of precipitation is expected by Monday morning with freezing levels in Rogers Pass climbing to 2000m.
Snowpack Summary
Up to 25cm of heavy storm snow affected by warm temps and wind has formed a cohesive slab over a widespread layer of large surface hoar. On solar aspects, the surface hoar sits on a sun crust. The Nov 5 surface hoar layer is buried down 80-100cm. On true north aspects, a basal weakness may become unstable with the recent additional snow loading.
Avalanche Summary
A widespread natural avalanche cycle accompanied new precipitation and wind yesterday afternoon and into the overnight period. Several large avalanches were observed from the highway corridor east of Rogers Pass, up to size 3. Avalanches starting high in the alpine triggered additional slabs at lower elevations.
Confidence
Intensity of incoming weather systems is uncertain
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.