The storm arrived mid-day Wednesday and deposited 15 cm by mid-afternoon. Forecast models are now calling for a total of 30-40 cm by the end of the day on Thursday. Watch out for fresh windslabs and overhead hazard at treeline.
Weather Forecast
A strong westerly flow is bringing moisture and wind across the region through until early Friday morning. Forecast models are calling for another 20-25 cm on Thursday for a total of 35-40 through the whole storm. Expect strong Westerly winds at ridge crests and temperatures steady around -5. Clearing and cold air for the weekend.
Snowpack Summary
Windslabs forming in alpine and treeline areas starting late Wednesday with drifts up to 30cm deep in the lee. These slabs will continue to build overnight and should be easy to trigger by Thursday. This new snow overlies a weak, facetted base which produces test failures on the Oct 26 melt-freeze crust 30-40 cm above the ground.
Avalanche Summary
No new avalanches reported today. Sunshine Village reported that the windslabs were just starting to become stiff enough to create a soft slab late in the afternoon.
Confidence
Forecast snowfall amounts are uncertain on Thursday
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.