Avalanche Forecast
Regions: Dogtooth, East Purcell, Purcells, West Purcell.
Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
Confidence
Moderate
Avalanche Summary
Persistent and wind slab avalanches have been reported daily in the Purcells. Preliminary reports from Saturday include a size 2 wind slab that stepped down to a persistent weak layer. On Thursday, two size 1.5 slabs were remotely triggered from 60 m away in an alpine bowl, and two naturally triggered persistent slabs were observed on north and east alpine aspects. More avalanche activity has been reported in the central Purcells near Invermere than in the Dogtooth Range.
Snowpack Summary
10 to 20 cm of recent snow and southwest wind have formed small wind slabs on lee aspects at treeline and above.
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
Saturday Night
Partly cloudy. 20 km/h southwest ridgetop wind. Treeline temperature -10 °C.
Sunday
Cloudy with 1 to 4 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -7 °C.
Monday
Cloudy with 5 to 10 cm of snow above 2000 m and rain below. 60 km/h southwest ridgetop winds. Treeline temperature 0 °C. Freezing level 2100 m.
Tuesday
Cloudy with 2 to 5 mm of rain. 20 km/h southwest ridgetop winds. Treeline temperature +1 °C. Freezing level 2400 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.
- Be aware of the potential for large, destructive avalanches due to deeply buried weak layers.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
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
10 to 20 cm of recent snow and southwest wind have formed wind slabs on lee aspects at treeline and above.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2