Avalanche Forecast
Regions: Bull, East Purcell, Purcells, St. Mary.
New snow lands on a variety of surfaces, assess bond of new snow as you change aspect and elevation.
Take extra caution when transitioning into wind affected terrain.
Confidence
Moderate
Avalanche Summary
Friday: Cornice falls were reported to have triggered large avalanches, mostly contained within the surface snow.
Thurs: One person was buried in an avalanche in Pedley Pass, just east of the forecast area. See details about that avalanche and a few nearby in these MINs.
Wed: Numerous, small natural and human triggered dry loose avalanches were reported in steep terrain, as well as a few small rider and explosive triggered slab avalanches.
Snowpack Summary
The upper snowpack is currently quite variable. New snow falls on a sun crust on solar aspects, and surface hoar or facets in sheltered areas or north aspects. The new snow is being wind redistributed by moderate southwest winds into fresh wind slabs.
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
Sunday Night
Mainly cloudy, with up to 12 cm snow. 15 to 25 km/h southwest ridgetop wind. Freezing level falling to 1400 m.
Monday
A mix of sun and cloud, with a possibility of isolated flurries. 10 to 20 km/h west ridgetop winds. Treeline temperature -6 °C.
Tuesday
A mix of sun and cloud, with isolated flurries, up to 2 cm. 10 to 20 km/h southwest ridgetop winds. Treeline temperature -1 °C.
Wednesday
A mix of sun and cloud, with isolated flurries. 10 to 20 km/h southwest ridgetop winds. Treeline temperature -1 °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.
- Pay attention to the wind; once it starts to blow, sensitive wind slabs are likely to form.
Avalanche Problems
Storm Slabs
The surface beneath the new snow varies from surface hoar, surface facets, or sun crust. Expect deeper deposits and more reactive slab in lee areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 1.5
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