Avalanche Forecast
Issued: Dec 20th, 2024 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.
Avalanche Canada,
Avalanche Canada
Choose sheltered, low-consequence terrain. Recently formed wind slabs in combination with buried weak layers necessitate a conservative approach.
Summary
Confidence
Moderate
Avalanche Summary
After the storm on Wednesday, numerous natural storm and wind slab avalanches were observed throughout the region (size 1-2) that likely ran during the storm.
On Thursday, explosive control in the Invermere area produced two size 2 deep slab avalanches from east-facing treeline terrain.
Snowpack Summary
Up to 20 cm of recent snowfall accompanied by southwest winds created wind slabs and scoured surfaces at alpine and treeline elevations.
The mid-snowpack may hold a weak layer of surface hoar or facets on shaded slopes and a sun crust on south-facing slopes, buried 20–40 cm deep.
Near Invermere, the snowpack base is weak, with faceted snow over an October crust. This layer likely exists region-wide but has only shown signs of instability near Invermere.
Weather Summary
Friday Night
Cloudy with up to 1 cm of new snow. 10 to 30 km/h southwest ridgetop wind. Treeline temperature -3 °C.
Saturday
A mix of sun and cloud with isolated flurries. 5 to 25 km/h southwest ridgetop wind. Treeline temperature -4 °C.
Sunday
A mix of sun and cloud with isolated flurries. 10 to 40 km/h southwest ridgetop wind. Treeline temperature -5 °C.
Monday
Cloudy with up to 2 cm of new snow. 10 to 40 km/h southwest ridgetop wind. Treeline temperature -4 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Recently formed wind slabs may remain reactive to human triggering at upper elevations.
Wind slabs have the potential to step down to buried weak layers, resulting in larger-than-expected avalanches.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Deep Persistent Slabs
In the Invermere area, weak faceted snow at the base of the snowpack remains a concern. Avalanches have occurred on steep, smooth north-facing slopes where the snowpack is shallow and weak.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 21st, 2024 4:00PM
