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.
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.
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.
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 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.
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.
