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.
astclair,
Avalanche Canada
Pay attention to how the wind has drifted snow as you gain elevation. Areas with drifted snow over a crust may be reactive to human triggering, especially near ridges and roll-overs.
Summary
Confidence
Weather Forecast
Wednesday night: Mainly cloudy, moderate west wind at ridgetop, isolated convective flurries with up to 5 cm of snow, freezing level near 800 m.
Thursday: Mostly cloudy, light northwest wind, isolated light flurries with trace accumulations, temperatures around -5 C near treeline, freezing level 500 m.
Friday: Cloudy, 5-15 cm of snow with an intense storm moving in overnight, moderate southwest wind gusting strong at ridgetop, temperatures rising to -3 C near treeline, freezing level rising to 700 m.
Saturday: Cloudy, 50-80 cm of snow expected to accumulate by mid-morning, strong southwest wind, temperatures rising to +2 C overnight during heaviest precipitation and dropping through the day, freezing level rising to 1100m and dropping to 500 m by end of day.
Avalanche Summary
No recent avalanche activity has been reported.
Small loose dry avalanches were observed out of steep terrain on Monday.
Snowpack Summary
At upper elevations north in the region, 5-15 cm of snow has added to accumulations from earlier this week. Moderate southwest winds have likely redistributed available snow into dense wind slabs in wind-exposed areas. These wind slabs may be reactive to human triggering in immediate lee terrain features (for example, just down-wind of ridges), particularly where the snow is not well-bonded to the buried crust that formed during the last big rain event.
We have a lot of uncertainty about the composition and reactivity of this widespread crust interface. There have been reports in the north of the region of surface hoar above the crust at upper elevations. Check out this MIN report from Sunday that shows these surface hoar crystals. As snow gradually accumulates and settles into a cohesive layer above it, we are vigilantly tracking this layer ahead of the incoming weekend storm. Send us your observations of what's above the crust where you are travelling using the Mountain Information Network.
Last week's rainy atmospheric river event has eroded snow depths at and below treeline to below the threshold depth for avalanches.
Terrain and Travel
- Be alert to conditions that change with elevation and wind exposure.
- Wind slabs may be poorly bonded to the underlying crust.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Problems
Wind Slabs
Recent snow and wind have formed dense slabs in wind-exposed areas at upper elevations. These wind slabs may be reactive to human triggering, especially where the snow is not well bonded to a buried crust.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 9th, 2021 4:00PM
