Storm slabs and a persistent weak layer are contributing to unstable snow conditions.
Use conservative route selection and resist venturing into complex terrain
A persistent weak layer of large surface hoar/ facets/ crust from late Januray is buried 40 to 80 cm and remains a significant concern. Avalanche activity has been prevalent on it this week, including some remote triggering.
Up to 40 cm of recent snow combined with strong winds built storm slabs on Saturday night. These slabs will be thickest and most reactive on lee slopes near ridgetops, and in areas where they overlie a new surface hoar layer.
Numerous natural, rider-triggered and remote-triggered persistent slab avalanches (up to size 3) were reported over the past week. Widespread wet loose sluffs up to size 2 were also observed.
Avalanches are becoming less frequent and smaller (mostly size 1–2), but accidental triggering of the persistent weak layer continued on Saturday.
Keep in mind that human triggering of large slabs remains possible even as natural activity tapers off.
15 to 40 cm of settling storm snow is covering a new layer of surface hoar and/or a melt-freeze crust in many areas. This may make storm slabs more reactive. Southwesterly winds during the storm built thicker slabs on lee slopes near ridgetops.
Some of the new snow may have fallen as rain at lower elevations. Solar aspects and lower elevations may be crusty.
The late January persistent weak layer, consisting of surface hoar/facets/crust, is buried 40 to 80 cm. It has surprised people with its reactivity over the past week, especially in sheltered treeline features.
The mid and lower snowpack is well settled with no layers of concern.
Sunday Night
Mostly clear skies. 20 km/h west ridgetop wind. Treeline temperature -6 °C.
Monday
Mostly cloudy. 20 km/h southwest ridgetop wind. Treeline temperature -7 °C.
Tuesday
Mostly cloudy. 0 to 5 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -7 °C.
Wednesday
Mix of sun and clouds. 2 to 4 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -8 °C.
More details can be found in the Mountain Weather Forecast.
