Hazard levels could be higher than forecast if the snowfall arrives earlier than expected. Backcountry users should keep a close eye on local conditions.
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
Tuesday and Wednesday will remain primarily windy (up to 90km/h from the SW), with daytime high temperatures near -7. When it comes to snowfall amounts there is significant disagreement between the models, with the most "optimistic" calling for 25cm by Wednesday evening.
Avalanche Summary
Natural avalanche activity has tapered off, but recent slides up to size 2.5 have been observed in the Alpine and Treeline elevation bands. Keep in mind that human triggering is still likely.
Snowpack Summary
A few convective flurries through the day on Monday put a light dusting on the surface. Recent storm snow has settled to an average of 40cm at Treeline. Widespread wind slabs are present in Alpine and Treeline terrain in lee and cross-loaded features. There has been lots of cracking, whumpfing, and skier triggered avalanches on the Dec 10th surface hoar and facet interface down 40-50cm. In addition, recent natural avalanches have stepped down to the October crust with fracture depths over 1 metre in some cases.
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.