Avalanche Forecast
Issued: Dec 26th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
zryan,
Avalanche Canada
Avoid wind-loaded areas and keep in mind that a weak layer of surface hoar is still buried within the range for large human-triggered avalanches.
Summary
Confidence
Avalanche Summary
Over the weekend, numerous skier-triggered wind slabs up to size 2 were reported in the alpine and treeline. Check out this MIN for an example. A skier-triggered size 2 persistent slab occurred in the Selkirks east of Revelstoke on a northeast aspect in the alpine on Saturday.
On Monday, solar input trigged a few size 1 to 2 natural storm slabs in southerly alpine terrain, suspected to be failing on a weak layer of surface hoar.
Snowpack Summary
Up to 10 cm of new snow overlies heavily wind-affected surfaces in the alpine and exposed areas at treeline from recent strong winds. Below treeline a new crust is on or near the surface.
The mid pack contains several layers of note; a layer of surface hoar and a crust down 20 to 50 cm, a significant crust from the early December rain event down around 60 cm and a layer of surface hoar down 60 to 100 cm.
The make up of the lower snowpack is variable throughout the region, in shallower snowpack areas, basal facets may exist
Weather Summary
Tuesday Night
Clearing. South alpine wind easing to 15 km/h. Treeline temperature -3 °C. Freezing level dropping to valley bottom.
Wednesday
Cloudy with sunny periods and isolated flurries. South alpine wind 20 to 40 km/h. Treeline temperature rising to -1 C. Freezing level rising to 1500 m.
Thursday
Mainly cloudy with snowfall, up to 5 cm accumulation. South alpine wind 15 to 40 km/h. Treeline temperature -2 °C. Freezing level 500 to 1500 m.
Friday
A mix of sun and cloud with isolated flurries. South alpine wind 15 to 30 km/h. Treeline temperature -2 °C. Freezing level 500 to 1000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Stay off recently wind loaded slopes until they have had a chance to stabilize.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Wind Slabs
Strong southerly winds in the past few days have formed wind slabs in lee areas in the alpine and treeline.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A layer of surface hoar is down 60 to 100 cm in the snowpack. This layer is still concerning where a thick crust is not found above it.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 27th, 2023 4:00PM
