A persistent weak layer is present at all elevations and could produce large destructive avalanches if triggered. Careful terrain choices are recommended given the uncertainity about this problem.
A layer of facets that formed during the period of arctic air is found down 30 to 60 cm. This layer produced natural avalanches last week, and recent snowpack observations suggest it's still reactive to human triggering. It is likely most reactive at treeline, where surface hoar could also exist as part of this layer.
In the past few days, we received several reports of previous natural avalanches up to size 2.5. These avalanches released on a 30 to 60 cm deep facet layer and occurred at all elevations and on a variety of aspects. Check out this MIN report from our field team on Friday for some photos and a good summary of this activity.
Recent snowfall has been wind-affected in exposed terrain. In wind-sheltered terrain, this recent snow sits on a layer of facets and surface hoar that formed during the mid-December Arctic outbreak. This layer is 30 to 60 cm deep and recent avalanche activity and snowpack tests suggest human-triggering is possible. Below treeline, a thin crust can likely be found at or near the surface.
Tuesday night
Cloudy, no precipitation, 30 km/h wind from the southeast, treeline temperatures drop to -8 °C.
Wednesday
Mostly cloudy with sunny periods in the afternoon, no precipitation, 20 km/h wind from the southeast, treeline temperatures around -6 °C.
ThursdayMix of sun and cloud, no precipitation, 30 to 50 km/h wind from the southeast, treeline temperatures around -5 °C.
FridayCloudy with afternoon flurries brining up to 5 cm of snow, 40 to 60 km/h wind from the south, treeline temperatures warm to -5 °C.
More details can be found in the Mountain Weather Forecast.
