Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 2–4
Multiple weak layers are present between roughly 80 and 180 cm deep. Triggering any of these layers would likely produce large, destructive avalanches.
Heavy snowfall, warm temperatures and buried weak layers make for very dangerous avalanche conditions. Avoid all avalanche terrain.
Multiple weak layers are present between roughly 80 and 180 cm deep. Triggering any of these layers would likely produce large, destructive avalanches.
New snow and wind are forming fresh, reactive slabs and adding load to buried weak layers.
Loose wet avalanches will become increasingly likely as rain wets the upper snowpack at lower elevations.
Widespread avalanche activity up to size 4 has been reported at all elevations over the past week. Avalanches have been triggered naturally, by riders, vehicles, and aircraft, many triggered remotely from a distance away. They have run on various buried weak layers detailed in the snowpack summary.
Large, destructive avalanche activity can be expected to continue as heavy snowfall further stresses these layers.
Heavy snowfall adds load to a precarious snowpack. At upper elevations, wind loads new snow into leeward terrain features. At lower elevations, the rain line creeps up to 1400 m by the end of Saturday.
Three problematic layers persist in the mid-snowpack.
One or two surface hoar layers buried in February (depending on location) are found roughly 60 to 120 cm below the surface, and in some areas these sit on a thin crust.
A deeper, widespread layer buried in late January, made up of surface hoar, facets, and/or a crust, is roughly 100 to 180 cm deep. Surface hoar within this layer is most preserved and largest in sheltered terrain at treeline and below.
Friday Night
Cloudy. 5 to 15 cm of snow. 50 km/h west ridgetop wind. Treeline temperature -4 °C.
Saturday
Cloudy. 15 to 25 cm of snow. 50 km/h west ridgetop wind. Treeline temperature -2 °C. Freezing level 1700 m.
Sunday
Mostly cloudy. 20 to 30 cm of snow. 50 km/h west ridgetop wind. Treeline temperature -3 °C. Freezing level 1600 m.
Monday
Mix of sun and clouds. 2 to 10 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -10 °C.
More details can be found in the Mountain Weather Forecast.