Regions
Northwest Inland.
Hazard forecast is highly dependent on how much snow accumulates during the incoming storm.
Confidence
Fair - Due to the number and quality of field observations
Weather Forecast
A Pacific low will deliver another round of moderate snowfall beginning Wednesday and continuing into next weekend. Strong southwesterly winds will accompany the incoming precipitation . Freezing levels will stay around the 1500M mark , but drop to around 500m on Wednesday, then rise again to 1500m for the rest of the storm cycle.
Avalanche Summary
There have been recent reports of skier accidental and natural wind slabs to size 1.5 occurring on north and east-facing terrain at treeline and above. On Tuesday we received a report of a size 2 skier triggered avalanche on Hudsons Bay Mtn. with skier involvement and injuries. Local skiers have also reported natural activity on solar aspects. With incoming storms, more wind slab development ( and avalanches ) can be expected.
Snowpack Summary
10-20cm of snow and strong SW winds from the previous storm built reactive wind slabs in exposed lee terrain. Snow and winds on Sunday have added size and destructive potential to the developing wind slab problem. There are a variety of interfaces including older wind slabs, hard crusts, surface hoar, and/or surface facets buried below the recent storms snow. At the base of the snowpack, weak facets may be found. Cornices are getting to be large and potentially unstable. Solar aspects may become active in the afternoons.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.