Avalanche Forecast
Issued: Jan 10th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
mconlan,
Avalanche Canada
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.
Summary
Confidence
Moderate - Forecast precipitation (either snow or rain) amounts are uncertain.
Weather Forecast
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.
Avalanche Summary
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).
Snowpack Summary
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.Â
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).
Terrain and Travel
- Watch for fresh storm slabs building throughout the day.
- Be careful as you transition into wind affected terrain.
- Be aware of the potential for large avalanches due to the presence of buried weak layers.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Storm Slabs
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.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
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.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 11th, 2021 4:00PM
