Avalanche Forecast
Issued: Dec 8th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
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Avalanche Canada
Danger will remain elevated at upper elevations due to strong westerly winds.
Summary
Confidence
Moderate - A small change in the upper snowpack could dramatically change avalanche conditions.
Weather Forecast
Unsettled weather until the next storm arrives on Saturday.
WEDNESDAY NIGHT: Cloudy with scattered flurries brining 5-10 cm of snow, moderate wind from the southwest with gusts to 50 km/h, treeline temperatures drop to -10 C.
THURSDAY: Mostly cloudy with scattered flurries bringing up to 5 cm of low density snow, moderate wind from the west with gusts to 50 km/h, treeline temperatures around -10 C.
FRIDAY: Mix of sun and cloud with some scattered flurries bringing trace amounts of snow, moderate wind from the southwest, treeline temperatures reach -8 C.
SATURDAY: Periods of snow with 10-20 cm by the afternoon, strong wind from the south, treeline temperatures reach -5 C.
Avalanche Summary
We expect strong wind and new snow to have caused some avalanche activity in the alpine on Wednesday (no reports at time of publishing). It will also likely leave wind slabs primed for human triggering. While there has been limited recent avalanche activity, pay close attention to changes in the low density snow because slabs could begin forming as this snow settles and gets blown around by wind.
Snowpack Summary
Recent storms delivered 30-60 cm of low density snow, with more dustings expected over the next few days. This snow sits above a crust that formed during last week's atmospheric river. This crust extends into the alpine (as high as 2200 m), and there is some concern about the bond of the recent snow to this crust. The surface snow should remain loose in sheltered terrain, but at higher elevations it has likely formed fresh wind slabs.
The snowpack structure is relatively simple beneath the crust. Treeline snow depths are roughly 150-200 cm with an early season crust layer in the lower snowpack. While some faceting has been reported around this crust, it does not appear to be problematic.
Terrain and Travel
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Avoid areas where the snow feels stiff and/or slabby.
- Closely monitor how the new snow is bonding to the crust.
- Be alert to conditions that change with elevation and wind exposure.
Problems
Wind Slabs
Recent weather has likely left unstable wind slabs at upper elevations, especially on the leeward side of ridges. Pay attention to the look and feel of the surface snow, as slab formation could also become more widespread. If slabs develop, they could be poorly bonded to the underlying crust.
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 9th, 2021 4:00PM
