Regions
Northwest Coastal.
Rising freezing levels, heavy precipitation, strong winds, and a layer or recently buried surface hoar are a recipe for High avalanche danger!
Weather Forecast
A series of powerful storms is going to wallop the coast over the coming days bringing heavy precipitation and strong winds. Tuesday could see snowfall accumulations of between 25 and 40cm. with another 30cm expected by Friday. Winds will be strong from the SW and freezing levels should stay below 1500m.
Avalanche Summary
Recent reports of natural, rider and remotely triggered avalanches from the mountains around Shames suggest that the load on a layer of recently buried surface hoar has reached critical levels.
Snowpack Summary
Up to 70 cm of new storm snow may now overlie a variety of old surfaces including crusts, facets and surface hoar. The distribution of surface hoar is definitely my biggest knowledge gap, although it has been reported well into the alpine in the Bear Pass.
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.