Avalanche Forecast
Issued: Dec 10th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs and Wind Slabs.
CJ,
Avalanche Canada
Natural avalanche activity has been limited, but human triggering of the slab over the basal facets is likely in many locations...keeping us in the Moderate-Considerable hazard rating. This will likely remain for some time. Conservative terrain choices are recommended.
The thin weak snowpack also means hitting buried rocks or sticks is more likely, so travel carefully.
Summary
Confidence
Moderate
Avalanche Summary
Multiple skier and explosive-triggered avalanches between size 1 and 2 have occurred at alpine and treeline elevations over the past week on all aspects. Some of these failures initiate as wind slabs and then scrub down to the basal facets, while others fail directly on the basal facets. Lots of whumpfing and cracking on the basal facets have also been observed. We expect these conditions to persist for quite a while.
Snowpack Summary
Recent snow and moderate SW winds have formed wind slabs at higher elevations. In most other areas, 20-50 cm of snow is forming a soft slab over a very weak base of facets, with occasional thin crusts at the interface. Average snowpack depths at treeline are between 60 and 90 cm.
Weather Summary
Some light flurries are expected on Sunday but no significant accumulations. Winds will be in the light range from the S-SW. Alpine temperatures will climb to -5 to -10°C before dropping to the -10 to -15°C range Sunday night.
Terrain and Travel Advice
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- Uncertainty is best managed through conservative terrain choices at this time.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Deep Persistent Slabs
A 20-50 cm soft slab has formed over the very weak basal facets, with thin crusts at the interface in some locations. Human triggering is likely in steep terrain anywhere this slab is present, and whumpfing and cracking have been observed in many locations. Treat all steep terrain with caution. This problem will remain for the foreseeable future.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
10-25 cm of snow has fallen over the past several days with moderate S-W winds. This has formed soft wind slabs in lee areas. These slabs are relatively soft and small but still possible to trigger. The major concern is that if triggered, these may step down to the weak basal facets and result in larger avalanches.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Dec 11th, 2022 4:00PM
