A storm is forecast to impact the region Sunday night into Monday, with the most snow forecast for the south of the region. New slabs will form and it will load buried weak layers in the north of the region.
A couple of problematic layers may be found around 80 to 180 cm deep. The layers are primarily in the north of the region (e.g. Duffey, Hurley) and include weak layers of surface hoar and faceted grains above a hard melt-freeze crust. The likelihood of triggering a persistent slab has reduced, but the consequence of doing so remains high.
New storm slabs will form during Sunday night's storm, with the most forecast for the south of the region (e.g., Coquihalla). New wind slabs are expected to form at higher elevations, as the snow will fall with strong southwest wind.
SUNDAY NIGHT: Cloudy with snowfall, accumulation 5 to 15 cm with the most in the south of the region, 40 km/h southwest wind, alpine temperature -4 C.
MONDAY: Cloudy with snowfall, accumulation 10 to 20 cm, 30 km/h southwest wind, alpine temperature -4 C.
TUESDAY: Cloudy with snowfall, accumulation 5 to 15 cm, 30 km/h south wind, alpine temperature -2 C.
WEDNESDAY: Cloudy with snowfall, accumulation 20 to 30 cm, 30 km/h southwest wind, alpine temperature -6 C.
Two large avalanches were observed near Duffey Lake on Saturday, described here and here. It is suspected that both avalanches were triggered naturally and on the weak layers described in the snowpack summary. Also, a notable skier-triggered avalanche occurred near Whistler, not far from this region (see the Sea to Sky bulletin for more info).
New storm and wind slabs will form during Sunday night into Monday's storm. The storm is expected to drop around 10 to 30 cm of snow, with the most in the west of the region. The storm will come with strong southwest wind so wind slabs are expected at higher elevations. In sheltered areas, this snow may overlie surface hoar.
A melt-freeze crust from early December is found around 80 to 180 cm deep in the snowpack. This crust may have surface hoar or sugary faceted grains sitting above it. This persistent weak layer is most prevalent in the north (e.g., Duffey Lake, Hurley).
