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 Wind Slabs and Persistent Slabs.
wlewis,
Avalanche Canada
Recent storm snow will remain reactive to human triggers, take care when moving into wind affected terrain.
Continue to make conservative terrain choices as uncertainty exists around buried weak layers particularly at treeline elevations.
Summary
Confidence
Avalanche Summary
Two persistent slab avalanches were reported to size 2 (remotely triggered), failing on the persistent weak layers buried mid November occurred on Friday, as new snow added load to the snowpack. Activity occurred from 1800-2300 mostly in sparsely treed terrain.
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
About 30 cm of new snow has been redistributed by moderate southwest winds at higher elevations. 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 persistent layer of surface hoar, crust, and faceted crystals is the primary concern within the snowpack. This layer has been most reactive at treeline between 1700-2200 m, but it was also observed as low as 1450 m and on all aspects.
Snowpack depths are highly variable and range from 90cm at treeline to 200cm in the alpine in wind affected locations.
Weather Summary
Saturday Night
Cloudy with up to 8cm of new snow possible. Easing southerly winds. Freezing level below valley bottom.
Sunday
Mostly cloudy. Flurries in the morning bringing trace amounts of new snow and then clearing in the afternoon. Alpine high of -6. Light easterly winds.
Monday
Mostly cloudy with the possibility of light flurries bringing trace amounts of new snow. Alpine high of -9. Light easterly winds.
Tuesday
Mostly cloudy. No snow expected. Alpine high of -9. Light easterly 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.
- 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
Wind Slabs
Southwest winds have redistributed recent snow into wind loaded features on west, north and east facing slopes at treeline and above. Wind slab avalanches could step down to deeper layers resulting in larger destructive avalanches.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar and facets from mid November is buried 50 to 90cm deep. Two notable large and surprising avalanches occurred on this layer on Friday.
Use extra caution at treeline where this layer is more prominent and look for signs of instability like shooting cracks, whumpfing and recent avalanches. Read our newest blog to learn more about this concerning layer and how to manage it.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 11th, 2022 4:00PM
