Avalanche reports point to a surface hoar layer that may keep wind slabs reactive longer than usual. Sporadic deeper releases mean terrain choices should stay on the conservative side.
Rider-triggerable slabs may be found below ridgetops and in cross-loaded terrain. A layer of surface hoar buried in early January is reaching a tipping point as slabs form over it. Triggering it could lead to wide propagations.
Triggering the early December surface hoar layer is becoming unlikely, but if triggered it will be a large avalanche. Treat steep openings at treeline and shallow, rocky start zones with extra caution.
On Sunday, there were several small rider-triggered wind slabs on east to southeast aspects at treeline. Check out this MIN report for a good sample of the issue.
No avalanches have been reported on the early December persistent weak layer since January 6, northwest of Kaslo. However, whumpfs have been reported, which could be this layer.
Expect to find 20 to 30 cm of soft snow in sheltered areas, and wind slabs below exposed alpine and treeline ridges.
Below the recent snow, there are potentially a couple different layers of large, feathery surface hoar crystals. They may be resting on a crust on slopes that face the sun.
A widespread surface hoar/facet/crust layer from early December is buried 70 to 120 cm. This layer is trending to unreactive in much of the region, but it's not fully healed. It was most recently active south of Trout Lake and east of Slocan Lake on north through east-facing slopes between 1700 and 2300 m.
At treeline, snow depths range from 135 to 200 cm.
Tuesday night
Cloudy with isolated flurries. 10 to 15 km/h southwest ridgetop wind. An above freezing layer lingering between 1700 and 2500 m.
Wednesday
Mainly sunny. 10 to 30 km/h southwest ridgetop wind, increasing. Above freezing layer lingering between 1700 and 2500 m. Treeline temperature around 0 °C.
Thursday
A mix of sun and cloud with scattered flurries bringing 1 to 5 cm of snow. 40 to 60 km/h southwest ridgetop wind. Above freezing layer breaking down and treeline temperature falling to -5 °C.
Friday
Mainly cloudy with isolated flurries. 30 km/h northwest ridgetop wind. Treeline temperature falling to -8 °C.
More details can be found in the Mountain Weather Forecast.
