Avalanche Forecast
Issued: Dec 7th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
wlewis,
Avalanche Canada
Choose conservative terrain, especially in areas that didn't see much rain. Surface hoar is still reactive to human triggers
Minimize exposure to large avalanche paths and overhead hazard
Summary
Confidence
Avalanche Summary
A widespread natural cycle occurred on Tuesday and Wednesday, with large storm slabs, and wet avalanches in areas that received mostly rain. Avalanches ran on the buried surface hoar layer or within the storm snow.
While storm snow avalanches are tapering off, the highest danger for continued reactivity exists in areas where the rain crust thins, or does not exist. Remotely triggered avalanches occurred in these conditions in nearby regions, on the buried surface hoar.
Snowpack Summary
10-20 cm of recent snow covers a widespread crust from the rain. In the south, this crust is up to 25 cm thick and extends to ridgetop. The crust thins to around 5 cm as you move north from Revelstoke, and is observed up to 2100 m near Valemount.
The greatest concern is a large and weak layer of surface hoar, generally found 45-80 cm deep. This surface hoar sits on a thin sun crust on steep south-facing slopes. In some areas, the surface hoar has been saturated by the rain and has begun to decompose. We have uncertainty about the extent of this and its effect on reactivity.
The mid-pack is generally well-settled. Lower in the snowpack a crust with weak facets beneath it can be found 20 cm off the ground.
Weather Summary
Thursday Night
Mostly cloudy, up to 5 cm of snow is possible in the east of the region as the front exits. Freezing levels drop overnight to valley bottom.
Friday
A mix of sun and cloud, with westerly winds 20-40 km/h. Freezing levels at valley bottom. No snowfall expected. Treeline temperatures around -8 °C.
Saturday
A mix of sun and cloud with light snowfall possible in the afternoon delivering trace amounts. Freezing levels sit at valley bottom, treeline temperatures around -8 °C. Southwest winds increase to 50-70 km/h.
Sunday
Cloudy with up to 10 cm of snow possible. Winds ease to 40 km/h from the west. Freezing levels remain at valley bottom. Treeline temperatures around -7 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Use careful route-finding and stick to moderate slope angles with low consequences.
Problems
Storm Slabs
Expect greater reactivity where slabs sit on a layer of buried surface hoar (think convex rolls and sheltered treeline areas), near ridgelines where winds have deposited deep pockets of snow, and where no rain crust exists above.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 8th, 2023 4:00PM
