Avalanche Forecast
Issued: Dec 17th, 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.
lbaker,
Avalanche Canada
Avalanche activity is decreasing however we continue to receive daily reports of large human-triggered avalanches on the persistent weak layer. Be patient as this layer continues to stabilize.
Don't forget that with cold temperatures and some of the shortest daylight hours of the year, any sort of incident (even broken equipment) could quickly become an epic.
Summary
Confidence
Avalanche Summary
Avalanche activity is slowly decreasing since early this week, however spooky, remote-triggered avalanches continue to be reported. On Friday in the northern Selkirks skiers remotely triggered a size 2 avalanche which sympathetically triggered a 2.5 avalanche on an adjacent path. These avalanches occurred at 2300m on a southeast aspect. Throughout the region, several machine accidental avalanches were reported to size 2.
On Thursday, skiers remotely triggered a large size 2 avalanche in the Monashees north of Hwy1. This avalanche occurred around 1900 m on an east aspect and was triggered from about 40 m away by skiers on a low-angle bench.
On Wednesday, skiers triggered several size 1-2 slab avalanches in the Selkirks, including a couple of size 1.5 avalanches remotely triggered in treeline openings around 1900-2000 m.
MondaySnowpack Summary
Snowpack depths at treeline range from 100 - 150 cm. In the alpine, snowpack depths are highly variable from extensive wind-affect in many locations.
Surface: 5 cm of new snow now overlies 5-8 mm surface hoar in sheltered areas. On steep solar slopes, new snow overlies a sun crust. Moderate westerly winds have built thin wind slabs in alpine lees.
Upper-pack: 40-50 cm settling snow overlies a weak layer of 5 mm surface hoar in sheltered and shaded terrain and a sun crust on sunny south-facing slopes.
Mid-pack: Buried 60-90 cm deep, is a persistent weak layer of surface hoar, crust, and faceted crystals. 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.
Lower-pack: Below the mid-November layer is a generally weak, faceted snowpack.
Weather Summary
Saturday night
Partly cloudy with isolated flurries, 2 cm accumulation. Light southwesterly ridgetop winds. Overnight alpine temperatures drop to -20 C.
Sunday
Colder, the arctic air settles in. Cloudy with sunny periods. Light northeasterly ridgetop winds. An alpine daytime high temperature of -21 C.
Monday
Sunny skies and light northeasterly ridgetop winds. An alpine daytime high temperature of -25 C.
Tuesday
Sunny with cloudy periods. Light southwesterly ridgetop winds. An alpine daytime high temperature of -20 C.
Tuesday
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be aware of the potential for large, destructive avalanches due to the presence of deeply buried weak layers.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
Problems
Persistent Slabs
There are now two persistent weak layers within the snowpack: 30-50 cm of recent snow covers a weak layer of surface hoar on shaded aspects and crust on steep solar aspects; many recent avalanches have failed on this layer.
A second weak layer of surface hoar and facets from mid-November is buried 60-90 cm in the region; this layer has recently surprised both professionals and recreationists with large human-triggered avalanches.
Read our featured blog to learn more about how to manage a persistent slab problem when travelling in the backcountry.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Moderate southwesterly winds have built thin wind slabs at higher elevations. Be cautious when transitioning into wind-affected areas, especially around ridge crests and roll-overs in steep terrain.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Dec 18th, 2022 4:00PM
