Avalanche Forecast
Regions: East Purcell, Purcells, St. Mary.
A persistent weak layer is in the snowpack, which means large avalanches are a concern.
Avoid large connected snow slopes, convexities and rocky areas.
Confidence
Moderate
Avalanche Summary
On Tuesday: Avalanche control happened in the region and produced large avalanches (up to size 3.5). The happened on north and east aspects in the alpine.
On Monday: There was extensive avalanche activity in the region. Large storm slab and wind slab avalanches occurred, with some stepping down to weak layers that are deeper in the snowpack, causing a persistent slab.
Snowpack Summary
Up to 20 cm of low density snow has been moderately redistributed by the wind in the alpine. This sits on a sun crust on solar aspects, and surface hoar or facets in sheltered areas or north aspects. Below treeline, a new surface crust likely exists from strong sunshine yesterday.
A few weak layers consisting of a crust, facets or surface hoar from February and January remain a concern, buried 30 to 60 cm.
A layer of facets from early December is buried 70 to 120 cm. In many areas, facets or depth hoar exist at the base of the snowpack. These deeper layers are not currently creating an avalanche problem.
Weather Summary
Wednesday Night
Mainly cloudy, with up to 5 cm of snow. 10 to 30 km/h southwest ridgetop winds. Treeline temperature -4 °C.
Thursday
Mainly cloudy, with 3 to 8 cm of snow. 20 to 50 km/h southwest ridgetop winds. Treeline temperature -3 °C.
Friday
A mix of sun and clouds, with flurries. 10 to 25 km/h southwest ridgetop winds. Treeline temperature -5 °C.
Saturday
A mix of sun and cloud, with isolated flurries. 10 to 30 km/h southwest ridgetop winds. Treeline temperature -3 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be aware of the potential for large, destructive avalanches due to deeply buried weak layers.
- Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
Avalanche Problems
Persistent Slabs
Several persistent weak layers exist, with the most problematic ones lying 30 to 60 cm deep. These layers remain a concern where there is no thick, supportive crust near the surface.
Aspects: North, North East, East, West, North West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1.5 - 3
Wind Slabs
The surface beneath the recent snow varies from surface hoar, surface facets, or sun crust.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2