Avalanche Forecast
Regions: Dogtooth, East Purcell, Purcells.
Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
Confidence
Moderate
Avalanche Summary
On Friday and Saturday, natural wind slab avalanches up to size 2 were reported near Invermere, including one which stepped down to a persistent weak layer. Last week, numerous persistent slab avalanches were reported in the central Purcells, including remote triggers from 60 m away.
Snowpack Summary
New snow falls over wind slabs at upper elevations, while rain wets the surface below 2000 m.
An interface from early March, 30 to 50 cm deep, consists of a crust on sunny slopes and lower elevations, and surface hoar or facets in sheltered, shaded upper elevations.
Persistent weak layers from February and January, including crusts, facets, and surface hoar, are buried 50 to 100 cm deep and remain a concern.
The bottom of the snowpack is composed of large facets, which are becoming reactive again, with some very large avalanches recently failing on this layer.
Weather Summary
Sunday night
Cloudy with 2 to 8 cm of snow. 30 to 40 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level rising to 2100 m.
Monday
Cloudy with 5 to 10 cm of snow above 2000 m and rain below. 20 to 40 km/h southwest ridgetop winds. Treeline temperature 0 °C. Freezing level 2200 m.
Tuesday
Cloudy with 2 to 5 mm of rain. 20 km/h southwest ridgetop winds. Treeline temperature +4 °C. Freezing level 2500 m.
Wednesday
Sunny. 10 to 20 km/h southeast ridgetop winds. Treeline temperature +6 °C. Freezing level 3000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
- Avoid areas with a thin or variable snowpack.
- Be aware of the potential for large, destructive avalanches due to deeply buried weak layers.
Avalanche Problems
Persistent Slabs
Triggering buried weak layers is most likely in wind-affected terrain on north and east aspects. Small avalanches in motion may trigger these deeper layers, potentially causing large and destructive avalanches.
Aspects: North, North East, East, West, North West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 3
Wind Slabs
New snow and wind are forming wind slabs in leeward terrain features at upper elevations.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2