Avalanche Forecast
Issued: Dec 16th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
dsaly,
Avalanche Canada
Keep backcountry travel low-risk and close to the car. First, there's a tricky weak layer problem. And second, with incoming really 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 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.
On Tuesday in the northern Monashees, a vehicle remote-triggered a size 2.5 persistent slab avalanche on the mid-November layer. Explosives control produced several size 3 and a size 3.5 persistent slab avalanches.
MIN reports from Monday outside the RMR area boundary document 2 large avalanches triggered by skiers, reported crown depths were 80 cm (Montana1, Montana2).
SundaySnowpack Summary
Snowpack depths are highly variable and range from 90 cm at treeline to 200 cm in the alpine in wind-affected locations.
Surface: 5-8 mm surface hoar has formed in sheltered areas on the surface of the snowpack. A sun crust is found on steep solar slopes above 2000 m. Northerly winds are creating wind slabs in lees and cross-loading features at higher elevations.
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
Friday night
Cloudy with isolated flurries, trace to 5 cm by morning. Light westerly ridge winds up to 20 km/h. Overnight alpine low temperature -16 C.
Saturday
Cloudy skies and isolated flurries, another trace to 5 cm. Light west ridge winds up to 20 km/h. Alpine high temperature -10 C and dropping quickly.
Sunday
Cold and grey, possible isolated flurries. Light northeast ridge winds up to 20 km/h. Alpine high temperature -20 C.
Monday
Very cold, but less windy. Calm to light winds, daytime high temperatures -22 C.
Monday
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.
- Be especially cautious as you transition into wind affected 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
Valid until: Dec 17th, 2022 4:00PM
