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 and Persistent Slabs.
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Avalanche Canada
Danger will remain elevated at upper elevations due to strong westerly winds. Some uncertainty remains about buried weak layers, so travel with extra caution.
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
Unsettled weather until the next storm arrives on Saturday.
WEDNESDAY NIGHT: Partly cloudy with some scattered flurries brining 1-5 cm of snow, strong wind from the southwest with gusts to 60 km/h, treeline temperatures drop to -12 C.
THURSDAY: Mix of sun and cloud with some 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 up to 5 cm of snow, strong wind from the southwest with gusts to 70 km/h, treeline temperatures reach -8 C.
SATURDAY: Periods of snow with 10-20 cm by the afternoon, strong to extreme 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.
There were two human triggered avalanches involving old snow earlier this week. One was a size 2 avalanche triggered in a north-facing bowl near Barkerville. This avalanche is suspected to have occurred on a 50 cm deep surface hoar layer that our field team also observed in that area. The other was triggered near McBride and released on a steep rocky slope near treeline (see this MIN report). The failure layer was likely an early season crust/facet layer.
Snowpack Summary
Recent storms delivered 30-50 cm of low density snow. There are a few potentially concerning layers underneath this snow including isolated layers of surface hoar around treeline and a slippery crust below 1800 m. The snow at higher elevations has been heavily impacts by wind, with scoured surfaces on windward terrain and wind slabs on leeward terrain. Regardless of the elevation, be alert to areas where the recent snow feels stiff or slabby.
An early season crust layer with some weak snow around it can be found 100-250 cm deep in the alpine, but may be more shallowly buried in some terrain. There is also evidence of a weak surface hoar layer 50 cm deep in the Barkerville area.
Terrain and Travel
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Caution around convexities or sharp changes in terrain.
- Avoid areas where the snow feels stiff and/or slabby.
- 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.
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A few recent reports of avalanches have raised concern about buried weak layers in the Cariboos. The main concern is a buried surface hoar layer near Barkerville, especially on north-facing slopes. We suggest conservative terrain selection as these layers could remain reactive with the added weight of recent snow.
Aspects: North, North East, North West.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Dec 9th, 2021 4:00PM
