Avalanche Forecast
Issued: Dec 8th, 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.
trettie,
Avalanche Canada
Conditions are more complicated than what meets the eye. Fresh wind slabs formed at upper elevations. Riders may be drawn to more sheltered areas around treeline to avoid these wind slabs, but should consider that this is where the persistent slab problem has been most problematic to date. Keep your terrain choices conservative and don't let good riding lure you into more hazardous terrain.
Summary
Confidence
Avalanche Summary
Over the past couple days several size 1 to 2 wind slab avalanches were reported in the region . These avalanches were generally in treeline and alpine terrain on northerly aspects. Some of these avalanches have failed on the mid november surface hoar layer. Many backcountry users have reported observing whumpfing and shooting cracks which are signs of instability.
Snowpack Summary
Recent new snow, about 30cm, has been redistributed by moderate winds forming wind slab. On south facing slopes this new snow has fallen on a sun crust and in sheltered terrain it sits over a layer of surface hoar.
Buried 50 to 90cm deep, a layer of surface hoar, crust, and faceted crystals is the persistent layer of concern. This layer has been most reactive at treeline between 1700-2200 m, but it was also observed as low as 1450 m and widespread whumpfing and cracking was reported throughout the region.
Snowpack depths range from 70 cm at treeline to 170 cm in the alpine, with wind-loaded areas exceeding 200 cm.
Weather Summary
Thursday Night
Around 5cm of new snow expected. Moderate southwest winds with a low of -10 at 1800m.
Friday
Mostly cloudy with a trace of new snow expected. Light to moderate southwest winds with a high of -8 at 1800m.
Saturday
Cloudy with up to 5cm of new snow. Moderate southerly winds in the morning becoming light in the afternoon. High of -7 at 1800m.
Sunday
Flurries in the morning bringing trace amounts of new snow and then clearing in the afternoon. High of -5 at 1800m. Light winds.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Expect slab conditions to change drastically as you move into wind exposed terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Persistent Slabs
A layer of surface hoar can be found down 50 to 90cm. If triggered this layer could produce large destructive avalanches. Use extra caution around treeline where surface hoar is more likely to be preserved.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Wind slab could be found on all aspects at treeline and above. Wind slab avalanches could step down to deeper layer resulting in large destructive avalanches. avoid wind loaded features.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 9th, 2022 4:00PM
