Avalanche Forecast
Issued: Dec 12th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
rgoddard,
Avalanche Canada
Buried weak layers and wind slabs are your main concern today.
Considered your up track and ski down accordingly. Check out our latest blog for advice on how to manage this problem.
Be on the lookout for whumpfing and shooting cracks.
Summary
Confidence
Moderate
Avalanche Summary
On Saturday there was a report of a skier triggering a size 2, large, avalanche. This was at treeline and on a north-facing slope. It failed on the buried weak layer and in some places was 45 cm deep. Local operators using explosives also triggered this layer and wind slabs producing several avalanches up to size 2 as well.
Snowpack Summary
About 10 to 20 cm of lighter snow sits on a variety of surfaces. In many places in the alpine it sits on stubborn windslabs. In sheltered areas it sits on more consolidated snow, ranging in 5 to 15 cm. Beneath that is a buried layer of surface hoar sits 20 to 45 cm deep and remains a layer of concern. On Saturday we received reports of several large avalanches failing on this layer. They were triggered intentionally through the use of explosives and accidentally by skiers.
Generally speaking, we have a thin snowpack. The bottom of the snowpack near the ground is very weak due to faceting.
The overall height of snow is highly variable throughout the region with around 40 to 140 cm in the alpine.
Weather Summary
Monday Night
Clear with cloudy periods, trace accumulation, winds northwest 10 km/h, temperature -5 C at 1500 m due to a temperature inversion.
Tuesday
A mix of sun and cloud, no accumulation, winds northwest 10 km/h, temperature -6 C at 1500 m due to a temperature inversion.
Wednesday
A mix of sun and cloud, trace accumulation, winds northwest 15 km/h, temperature -10 C at 1500 m.
Thursday
Sunny with cloudy periods, no accumulation, winds northwest 10 to 20 km/h, temperature -10 C at 1500 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Be especially cautious as you transition into wind affected terrain.
- Caution around convexities or sharp changes in terrain.
Problems
Persistent Slabs
Buried layers of surface hoar and facets are still a concern as more load is added. Suspect triggering to be its highest in areas where the snowpack is shallower.
This layer will be most evident in sheltered areas at treeline, where surface hoar may be preserved, and in wind-loaded areas at upper elevations where a cohesive slab above has formed.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Southwest winds continue to build wind slabs.
These slabs likely overlay a weak, sugary lower snowpack. If triggered, small avalanches may trigger a bigger avalanche by 'stepping down' to these weak crystals.
Aspects: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 13th, 2022 4:00PM
