Today is the start of the Winter Permit System. A valid winter permit is required to enter Winter Restricted Areas. Know before you go!
Weather Forecast
A brief storm is rolling through the region today, bringing 15-20cm of snow, with freezing levels remaining in the valley bottom and moderate SW winds at ridge top. By Tuesday afternoon, cold Arctic air will have slid into the Columbia's, bringing northerly winds, clear skies, and cold temp's. The Arctic air will stick around for few days.
Snowpack Summary
Recent observations suggest that the ~1m of storm snow is settling and bonding. Surface hoar layers down ~1m and 1.5m are still a concern but becoming more stubborn and hard to find. On high elevation N/NE aspects, there is a weak facetted base.
Avalanche Summary
Several large (size 3) avalanches were observed on Rogers Peak, Swiss Peak, and Hermit Mtn. They appear to be deep releases (80-100cm), but the crowns were filled in slightly, so the exact timing of their release is possibly Saturday. Isolated soft slabs to size 2 were observed from steep, north-facing terrain on Mt MacDonald yesterday.
Confidence
Intensity of incoming weather systems is uncertain
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.