Heightened avalanche conditions exist on wind-loaded slopes and in steep, rocky terrain. The likelihood of triggering deeply buried weak layers is reducing but the consequence of doing so remains high.
Riders may still trigger wind slabs due to snow transportation from recent southwest wind. The most suspect terrain features are wind-loaded pockets at higher elevations.
Weak surface hoar and/or faceted grains sit above a melt-freeze crust around 70 to 100 cm deep. The likelihood of triggering a persistent slab has reduced, but the consequence of doing so remains high.
SUNDAY NIGHT: Cloudy with isolated flurries, 20 km/h southwest wind, alpine temperature -6 C.
MONDAY: Cloudy with snowfall, accumulation 5 cm, 40 km/h southwest wind, alpine temperature -6 C.
TUESDAY: Cloudy with snowfall, accumulation 10 to 20 cm, 40 km/h southwest wind, alpine temperature -4 C.
WEDNESDAY: Cloudy with snowfall then clearing, accumulation 15 to 25 cm, 30 km/h west wind, alpine temperature -5 C.
A few small wind slab avalanches were triggered by riders on Saturday. They occurred on north to northwest aspects and around 2000 m.
Of note, a naturally-triggered size 3 deep persistent slab avalanche released on a southeast aspect at 2200 m in the Rossland range last Tuesday or Wednesday. The avalanche likely failed on the weak layers described in the Snowpack Summary and scrubbed to ground. Persistent slab avalanche activity has quieted in the past few days since this report. Although the likelihood of triggering these layers has reduced, the consequence of doing so remains high.
Lingering wind slabs may be found at higher elevations from strong southwest wind. In sheltered areas, recent new snow may overlie surface hoar.
Two weak layers are buried in close proximity to one another. They are 70 to 100 cm deep around Nelson and 50 to 80 cm deep around Rossland and other western parts of the region. The layers are composed of surface hoar and faceted grains and they overlie a hard melt-freeze crust. Many MIN reports describe these layers and their snowpack test results. The results suggest that it remains possible for riders to trigger these layers.
Another layer of faceted grains above a melt-freeze crust that formed in early November is upwards of 200 cm below the surface. This has been the suspected failure layer of a few very large avalanches that released last week in the Rossland range.
