Avalanche Forecast
Regions: East Purcell, Purcells, St. Mary.
Human triggered persistent slab avalanches continue to be reported.
Triggering is most likely on northerly aspects and in wind affected terrain.
Confidence
Moderate
Avalanche Summary
On Sunday, a skier remotely triggered a size 2 persistent slab avalanche from 50 m away. The avalanche failed on a wind loaded slope on a northerly aspect at treeline near Panorama. The weak layer was 40-150cm deep.
A naturally triggered size 2 deep persistent slab that scrubbed down to rocks was observed on northwest aspect in the alpine near Brisco.
Explosive triggered storm slabs were also reported up to size 2.5, primarily on northerly aspects in the alpine.
Snowpack Summary
30 - 50 cm of recent storm snow overlies a crust on sunny slopes and lower elevations, and surface hoar or facets on sheltered and shady upper elevations. Southwesterly wind formed slabs on lee features at treeline and above.
Several persistent weak layers consisting of a crust, facets or surface hoar from February and January remain a concern, buried 50 to 100 cm.
The bottom of the snowpack is composed of large facets in many areas.
Weather Summary
Monday Night
Partly cloudy, 10 to 20 km/h west ridgetop winds, treeline temperature -10 °C, freezing level valley bottom.
Tuesday
Mix of sun and cloud, 10 to 20 km/h west ridgetop winds, treeline temperature -6 °C, freezing level 1400 m.
Wednesday
Mostly sunny, 5 to 10 km/h southwest ridgetop winds, treeline temperature -5 °C, freezing level 1500 m.
Thursday
Cloudy, 20 to 30 km/h southwest ridgetop winds, treeline temperature -3 °C, freezing level 1700 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.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Even brief periods of direct sun could produce natural avalanches.
- Avoid steep, sun-exposed slopes when the air temperature is warm or when solar radiation is strong.
Avalanche Problems
Persistent Slabs
Human triggered persistent slab avalanches continue to be reported. Triggering is most likely on northerly aspects and in wind affected terrain.
Aspects: North, North East, East, West, North West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 3
Wind Slabs
New snow overlies a variety of surfaces, including surface hoar, facets, or a crust, which may make wind slabs more reactive and take longer to bond.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2
Loose Wet
Wet loose avalanches will become very likely when the sun comes out. Avoid overhead hazard from steep sunny slopes when the solar radiation is strong.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 1.5