New snow builds fresh storm slabs and adds load to a buried weak layer that has potential to produce large avalanches. It's a good day for conservative terrain choices.
A reactive layer of surface hoar is buried around 1 m 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 are building fresh and reactive slabs.
On Saturday, avalanche activity included
numerous natural wind slab avalanches up to size 2.5
persistent slab avalanches were mostly skier triggered size 1-1.5 or explosive triggered size 2-3.5
Last week, large natural persistent slab avalanches were widespread size 2 to 3.5. As new snow adds load to this layer, a resurgence in large natural avalanche activity can be expected.
New snow falls over settled or wind affected snow from last week. By the end of the day Monday, 30 to 60 cm of new snow is forecast to accumulate. The new snow arrives with wind, loading lee features at exposed elevations.
A problematic layer of surface hoar is now buried around 1 m deep or more. Widespread avalanche activity was observed on this layer during the storm last week.
The prominent mid-December crust is now buried around 1.5 m deep, and is present up to 2300 m. Triggering this layer is considered unlikely, except with large loads or in thin snowpack areas.
Sunday Night
Cloudy. 5 to 15 cm of snow. 50 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1200 m.
Monday
Cloudy. 15 to 25 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1400 m.
Tuesday
Mostly cloudy. 10 to 25 mm of precipitation as snow or rain at treeline. 40 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1900 m.
Wednesday
Mix of sun and clouds. 1 to 2 mm of rain at treeline. 40 km/h southwest ridgetop wind. Treeline temperature 2 °C. Freezing level 2600 m.
More details can be found in the Mountain Weather Forecast.
