Reactive persistent weak layers, combined with newly forming storm slabs, are keeping avalanche danger considerable at all elevations.
Stick to conservative terrain choices.
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, including many incidents of remote triggering.
5 - 20 cm of new snow is in the forecast for Friday. This will be adding to older settling storm slabs which may still be triggerable. Slabs will be most reactive on lee slopes near ridgetops and in areas where they overlie a surface hoar layer.
In the past few days, there have been numerous reports of natural, skier-triggered and remote-triggered avalanches across the region up to size 3. Many of these avalanches failed on, or stepped down to, the late January persistent weak layer. See photos below for some recent examples.
With more new snow and wind in the forecast, potentially burying another surface hoar layer, we expect the danger to stay elevated for several more days at least.
Up to 20 cm of forecast new snow may bury a new layer of surface hoar or sun crust, making storm slabs more reactive than usual. The heaviest snowfall is expected in the north, with much less in the south.
Below that, 15 to 40 cm of settling storm snow may be covering a second reactive layer of surface hoar or a crust from Feb 7th.
Lastly, the late January persistent weak layer of surface hoar/facets/crust, is buried 40 to 80 cm, except near Blue River, where it is over 100 cm deep. This layer has surprised people with its reactivity over the past week, especially in sheltered treeline features.
The remaining snowpack has no layers of concern
Thursday Night
Mostly cloudy. 2 to 10 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -5 °C.
Friday
Cloudy. 2 to 15 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -6 °C.
Saturday
Mostly cloudy. 5 to 20 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -6 °C.
Sunday
Mix of sun and clouds. 0 to 5 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -8 °C.
More details can be found in the Mountain Weather Forecast.
