Avalanche Forecast
Issued: Dec 17th, 2024 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
Avalanche Canada,
Avalanche Canada
Watch for ongoing wind slab formation throughout the day.
A weak layer from early December may become more reactive with the incoming snowfall and wind, and persistent slabs are possible.
Summary
Confidence
Low
Avalanche Summary
On Tuesday, a ski cut triggered a size 1 persistent slab avalanche at 2300 m in a deeper snowpack area near the Purcell Wilderness Conservancy. This failed on the early December surface hoar down 40 cm.
On Monday, a natural size 2 avalanche was reported on an east aspect at 2300 m near Bugaboo Provincial Park. In the Dogtooth, explosives triggered a size 1 avalanche on a north aspect in the alpine which is expected to have failed on the early December weak layer.
Snowpack Summary
New snowfall will continue to add to the 5-15 cm of snowfall which has accumulated since Sunday. Wind will continue to redistribute this snow in exposed terrain.
A weak layer from early December may include surface hoar and/or small facets on shaded slopes, and a sun crust on south slopes. In the Dogtooth and western Purcells, this layer is down around 40 cm and has been reactive recently. In the shallower snowpack areas around Invermere, the layer is only down 10-20 cm.
Around Invermere, the base of the snowpack consists of weak, faceted snow over a crust from late October. This layer likely exists throughout the region but has recently only been reactive in shallow snowpack areas around the Invermere.
Weather Summary
Tuesday Night
Cloudy with 4-8 cm of snow. 20-40 km/h southwest ridgetop wind. Treeline temperature -8 °C.
Wednesday
Cloudy with 8-12 cm of snow in the morning, and possible sunny breaks in the afternoon. 20-50 km/h southwest ridgetop wind. Treeline temperature -4 °C.
Thursday
Mostly sunny. 10-20 km/h southwest ridgetop wind. Treeline temperature -5 °C.
Friday
A mix of sun and cloud. 10-20 km/h southwest ridgetop wind. Treeline temperature -2 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and slopes above cliffs.
Problems
Wind Slabs
Watch for new wind slab development in exposed terrain on Wednesday.
Wind slabs have the potential to step down to a weak layer from early December resulting in larger than expected avalanches.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer from early December appears to be most reactive in the deeper snowpack areas including the Dogtooth and western Purcells. This layer may become increasingly reactive on Wednesday with loading from new snow and wind.
Aspects: All aspects.
Elevations: Alpine, Treeline.
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: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 18th, 2024 4:00PM
