Regions
Northwest Coastal.
Heavy precipitation and high winds will keep the hazard high until the storm snow gets a chance to bond.
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Wednesday: Pacific frontal system exits the area and moves off to the east. Freezing levels drop to valley bottom for most of the forecast area in between storms.Thursday: Freezing levels will rise late in the day to 1500 M as the next storm system drives onto the coast bringing high winds and heavy precipitation. Friday: Pacific frontal system moves through the coast and into the interior. Freezing levels lower as the storm moves east but will stay above 0c for the coast, precip. will remain light.
Avalanche Summary
Numerous size 2-3 avalanches have been observed in the bear pass area. These mainly occurred on north through east slopes that are lee to strong southwest winds.The warm new snow is likely not bonding well to the weak layers formed in early December. Heightened avalanche activity and conditions will continue through Wednesday. Lower elevations are experiencing moist or wet natural avalanches releasing at or near the ground. This will become less of a problem once the freezing levels start descending back down to valley bottoms. Lee slopes will be touchy at upper elevations until this storm snow gets a chance to bond.
Snowpack Summary
Heavy wet snow has fallen at upper elevations with freezing levels rising to 1500m during the last storm. Strong west winds have transported the new snow creating storm slabs that sit above a weak layer formed during the last cold snap. Surface hoar, and facets in the upper snowpack are now buried anywhere from 50 to 80cm from the surface by the recent stormShames area at 950m elevation suggested the mid and lower snowpack was composed of various faceted layers and a stiff 4 cm crust. Another crust can be found closer to the base of the snowpack. The recent precipitation will strengthen the snowpack at lower elevations, but may prove to be problematic with rapid wind loading at upper levels.
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.