Avalanche Forecast
Issued: Dec 19th, 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.
ldreier,
Avalanche Canada
Although avalanche activity on the persistent weak layers has decreased, it is important to stay vigilant. Maintain good travel habits and use decision-making tools.
This week's cold temperatures and short days can turn even small incidents like broken equipment into a very bad time. Bring lots of warm layers, hot drinks and a headlamp when venturing out.
Summary
Confidence
Moderate
Avalanche Summary
On Sunday, skiers triggered several small avalanches of size 1 below treeline about 40 cm deep. A small natural avalanche released on a northern aspect around 2000 m and there were several reports of whumpfing and shooting cracks.
On Saturday a size one, skier accidental, wind slab avalanche was reported on a southeast aspect at 2300 m.
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 2300 m 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.
Snowpack 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: 5-15 cm of recent snow 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: Cold temperatures are faceting the upper snowpack. 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
Monday Night
Clear, 20-30 km/h westerly wind, temperature low round -25 °C.
Tuesday
Sunny with cloudy periods, up to 5 cm new snow and up to 15 cm low-density snow in the very south of the region, 20 km/h westerly wind, temperature high at -23 °C.
Wednesday
Mix of sun and cloud, up to 5 cm low-density snow in the southern half of the region, 20-30 km/h northeast wind, temperature high around -26 °C.
Thursday
Sunny, 10-20 km/h northeast wind, temperature high at -25 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be mindful that deep instabilities are still present and have produced recent large avalanches.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- Avoid making assumptions about this layer based on the presence of aggressive tracks on adjacent slopes
Problems
Persistent Slabs
There are two persistent weak layers within the snowpack: 30-50 cm of snow covers a weak layer of surface hoar on shaded aspects and a crust on steep solar aspects; many avalanches failed on this layer last week.
A second weak layer consists of surface hoar and facets from mid-November and 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 westerly 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 20th, 2022 4:00PM
