Regions
Northwest Coastal.
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain on Thursday
Weather Forecast
Thursday: Moderate to locally heavy snowfall / Strong southwest winds / Freezing level at 500mFriday: Moderate snowfall / Strong southwest winds / Freezing level at 400mSaturday: Light snowfall / Moderate southwest winds / Freezing level at 500m
Avalanche Summary
Several natural and human triggered loose and storm slab avalanches to size 2 were reported on Tuesday. I expect ongoing storm slab avalanche activity with increasing size throughout the forecast period
Snowpack Summary
In some areas over 60cm of recent snowfall overlies a medley of old surfaces which include: weak surface facets, surface hoar, thin wind slabs, a scoured crust, or any combination thereof. Reports from the field indicate a poor bond between the new snow and these old surfaces with accounts of whumfing and easy, sudden planar snowpack tests. Strong winds and slight warming have added cohesion to the new storm slab, and have shifted the new snow into deeper, destructive wind slabs in exposed terrain. The mid and lower snowpack are generally strong and well-settled. Basal facets and depth hoar are likely to exist in some parts of the region, but triggering has become unlikely.
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.