Avalanche Forecast
Issued: Dec 9th, 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
Continue to make conservative terrain choices. We are inching closer to the tipping point where persistent slab avalanches become more reactive to rider triggering. Read our newest blog to learn more about this concerning layer and how to manage it.
Summary
Confidence
Moderate
Avalanche Summary
On Thursday several size 1 wind slab avalanches were triggered by skiers in treeline terrain. Several of these avalanches were remotely triggered, failing on buried surface hoar. Whumpfing and cracking were observed throughout the region.
Snowpack Summary
Recent new snow, about 30 to 50cm, has been redistributed by moderate southwest 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 60 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.
Snowpack depths range from 90cm at treeline to 200cm in the alpine.
Weather Summary
Friday Night
Flurries with up to 5cm of new snow expected. Southerly winds increasing throughout the night, strong by early Saturday morning. Low of -10 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 -6 at 1800m. Light easterly winds.
Monday
Mostly cloudy with the possibility of light flurries bringing trace amounts of new snow. Light winds and a high of -9 at 1800m.
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.
- Watch for newly formed and reactive wind slabs as you transition into wind affected 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
Southwest winds have redistributed recent snow into wind slab on west, north and east facing slopes at treeline and above. Wind slab avalanches could step down to deeper layers resulting in large destructive avalanches. avoid wind loaded features.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 10th, 2022 4:00PM
