Be aware of terrain where new wind slabs are forming, like ridges and high points. Manage cornices and our complicated snowpack by selecting routes that avoid or limit exposure to large avalanche paths with overhead hazards.
Roughly 15 to 20 cm of new snow has accumulated over the past 24 to 36 hours developing storm and wind slabs that are building over previous old wind slabs in open terrain features, storm snow in sheltered terrain, and burying a thin melt-freeze crust on south aspects from sunny skies on Wednesday.
Problematic weak layers are becoming spotty across the region, however recent large persistent slab avalanche observations continue to trickle in reminding us that these layers remain a concern in this region. Recent avalanches have been triggered by a mix of large loads like cornices.
A layer of large and weak facets sits near the base of the snowpack. This layer continues on a sporadic basis to produce very large avalanches that can travel far. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain, or by triggering a smaller avalanche that could step down to this layer. Cornices will continue to grow with new snow and wind and could be the large load needed to trigger deep persistent weak layers. Your best defense is to stay diligent in choosing low-consequence terrain away from overhead exposure.
Several natural, cornice, and human-triggered wind slabs up to size 2 were reported across the region on Wednesday.
A large size 3 avalanche was triggered by a rider in the Esplanades area on the deep persistent weak layer buried in November. Another reminder that this layer is still a player in this region.
Roughly 10 to 15 cm over the past 24 hours with the highest amounts in Revelstoke and north. Some wind redistribution of snow isolated to direct lees. New snow will bury a melt-freeze crust that can be found on steep south-facing slopes. Cornices continue to build new overhanging edges with this new snow and winds.
The mid-pack is generally well consolidated with a few operations reporting continued snowpack results on a spotty surface hoar layer down roughly 80 cm. Reports of large avalanches involving various layers of surface hoar/crusts and facets within the mid-pack depth are sporadic but are a reminder of the complicated snowpack across this region.
In the lower snowpack, a layer of large and weak facets from November near the base of the snowpack is slowly gaining strength but there continues to be low confidence in this layer. Large destructive avalanches are the result if this layer is triggered.
Thursday night
Cloudy with continued flurries tapering Friday morning, 5 to 10 cm accumulations, 10 to 20 km/h
Friday
Mainly cloudy, flurries with 2 to 5 cm accumulation during the day, with a short break before the snow starts again overnight. 15 to 20 km/h southwest winds, treeline temperatures -8 °C.
Saturday
Mainly cloudy, flurries with 5 to 10 cm accumulation, 20 to 30 km/h southwest winds, treeline temperatures -7 °C.
Sunday
Cloudy with flurries, 5 to 10 cm accumulation, 15 to 20 km/h southwest winds, treeline temperatures -6 °C.
More details can be found in the Mountain Weather Forecast.
