Avalanche Forecast
Issued: Dec 14th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
mconlan,
Avalanche Canada
Strong southwest wind and a bit of new snow may liven wind slabs at higher elevations.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations.
Weather Forecast
MONDAY NIGHT: Cloudy with snowfall, accumulation 2 to 5 cm, 20 to 30 km/h southwest wind, alpine temperature -8 C.
TUESDAY: Cloudy with snowfall, accumulation 5 cm, 30 to 50 km/h southwest wind, alpine temperature -6 C.
WEDNESDAY: Cloudy with snowfall, accumulation 5 to 10 cm, 60 to 80 km/h west wind, alpine temperature -7 C.
THURSDAY: Mix of sun and cloud with periodic snowfall, accumulation 5 cm, 20 to 40 km/h west wind, alpine temperature -9 C.
Avalanche Summary
A wind slab avalanche likely stepped down to the weak faceted grains described in the snowpack summary, forming a large avalanche near Smithers within the past few days.
Data in this region is very sparse. Please considering sharing your observations to the Mountain Information Network; even just a photo of your day helps. Thank you to those that have already submitted this winter.
Snowpack Summary
Wind from variable directions have affected the snow surface at and above treeline, forming wind slabs on all aspects. Strong southwest wind and small amounts of new snow are forecast for Tuesday. These slabs may overly a melt-freeze crust from early December, which may have weak and sugary faceted grains growing around it.
At the base of the snowpack sits the early-November crust with weak faceted grains below. These faceted grains have formed large avalanches in both the south and north of the region within the past week.
Snowpack depths vary substantially with aspect, elevation, and wind exposure. Below treeline the terrain may still be below the threshold for avalanches.Â
Terrain and Travel
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
Problems
Wind Slabs
Wind from variable directions has formed wind slabs on all aspects. Strong wind from the southwest is forecast for Tuesday, so the freshest slabs are expected to be on northwest to northeast to southeast aspects.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Weak faceted grains near the base of the snowpack have the potential of forming large and destructive avalanches. The most likely place to trigger this layer would be on shallow and rocky slopes. Smaller wind slab avalanches would also have the potential of stepping down to this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 15th, 2020 4:00PM
