Avalanche Forecast
Issued: Dec 7th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
swerner,
Avalanche Canada
Reactive wind slabs may exist at treeline and above. Watch and feel for signs of instability such as whumpfing, cracking, and new avalanches.
Concern remains for the persistent weak layers near the base of the snowpack where a small avalanche could possibly 'step down' initiating a larger one.
Summary
Confidence
Avalanche Summary
No new natural avalanches were reported on Tuesday. Explosive control in the southern part of the region showed several size 1 dry loose and persistent slabs.
Sunday produced several small (size 1-1.5) persistent slab avalanches from North and Northwest facing treeline. These avalanches failed on the Mid-November surface hoar layer.
We have very few observations from the field. If you do get out please consider reporting in the MIN.
Snowpack Summary
5 to 10 cm of new low-density snow fell by Wednesday. Consistent and strong westerly winds likely redistributed the new and old snow, forming fresh wind slabs in the alpine and treeline. In exposed terrain, some slopes have been scoured back to rock and in sheltered areas, 20-60 cm overlies a generally weak and sugary (faceted) lower snowpack. The prolonged cold temperatures have weakened the generally thin snowpack, promoting faceting as a whole. A buried layer of surface hoar sits 25-60 cm deep and remains a layer of concern, especially once a stiffer slab sits above it.
The overall height of snow is highly variable throughout the region with around 40-150 cm in the alpine.
Weather Summary
Wednesday Night
Cloudy with clear periods. Moderate southwest to westerly winds at ridgetop. Temperatures steady at -15 C.
Thursday
Mix of sun and cloud. Moderate to strong ridgetop wind from the southwest and temperatures slightly warmer near -11 C.
FridayMix of sun and cloud with isolated flurries. Light ridgetop wind from the southwest and a daytime high of -11 C and low -15 C.
SaturdayMostly cloudy with some sunny periods. Trace of new snow. Light southeast winds at ridgetop. ridgetop. Temperatures reach a daytime high of -13 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.
- 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.
- In times of uncertainty conservative terrain choices are our best defense.
Problems
Wind Slabs
Strong westerly winds may redistribute surface snow into fresh and reactive wind slabs in the alpine and open areas at treeline.
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, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Buried layers of surface hoar and facets have been reactive to human triggering in recent days. The most reactivity has been observed 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
Valid until: Dec 8th, 2022 4:00PM
