A new storm arriving Sunday will further stress a buried weak layer of surface hoar that has been reactive recently.
A reactive layer of surface hoar is buried 70 to 100 cm deep. Additional snow load will increase the likelihood of triggering, as well as the size of avalanches running on this layer.
New snow and wind will begin to build fresh slabs on Sunday.
Last week, widespread avalanche activity size 2 to 3, was observed on a recently buried layer of surface hoar on a variety of aspects at all elevations. Many were triggered by humans, including several remotely triggered from ridgetops or low angle terrain.
As new snow load accumulates over this layer, a resurgence in this kind of avalanche activity can be expected.
By the end of the day Sunday, up to 25 cm of new snow is forecast to accumulate over settling snow from last week. The new snow arrives with wind, loading lee features at exposed elevations.
A problematic layer of surface hoar is now buried 70 to 100 cm deep. Widespread avalanche activity was observed on this layer over the past week.
The prominent mid-December crust is buried 100 to 150cm deep, and is present up to 2300 m. Triggering this layer is considered unlikely, except with large loads or in thin snowpack areas.
Saturday Night
Mostly cloudy. 3 to 5 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -6 °C. Freezing level 800 m.
Sunday
Mostly cloudy. 10 to 25 cm of snow, higher amounts in the Monashees. 30 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level 900 m.
Monday
Mostly cloudy. 15 to 30 cm of snow. 50 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1500 m.
Tuesday
Mostly cloudy. 5 to 15 mm of rain at treeline. 50 km/h southwest ridgetop wind. Treeline temperature 1 °C. Freezing level 2200 m.
More details can be found in the Mountain Weather Forecast.
