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Avalanche Forecast

Mar 13th, 2025–Mar 14th, 2025
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: East Purcell, Purcells, St. Mary.

Assess how the new snow is bonding to underlying layers, especially in wind-loaded areas.

A buried persistent weak layer means avalanches could step down and become larger than expected.

Confidence

Moderate

Avalanche Summary

Thurs: A naturally-triggered deep persistent slab occurred near Invermere, 30-100 cm deep.

Tues: Avalanche control produced large avalanches (up to size 3.5) in the central-western part of the region.

Mon: Extensive avalanche activity with storm and wind slabs, some notably stepping down to deeper persistent weak layers.

Looking forward: We expect both wind slabs and persistent slabs to remain triggerable over the following days.

Snowpack Summary

Up to 25 cm of recent snow has formed fresh wind slabs near ridgetops on leeward north through east facing slopes, driven by southwest winds. The new snow sits on a sun crust on solar aspects, and surface hoar or facets in sheltered areas or north aspects. At lower elevations the snow surface may be moist or crusty. 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 make up the base of the snowpack.

Weather Summary

Thursday Night

Partly cloudy with trace amounts of snow possible. 15 to 30 km/h southwest ridgetop winds. Treeline temperature -10 °C.

Friday

A mix of sun and clouds. 15 km/h southwest ridgetop winds. Treeline temperature -7 °C.

Saturday

A mix of sun and cloud, with isolated flurries up to 2 cm. 10 to 15 km/h south ridgetop winds. Treeline temperature -6 °C.

Sunday

A mix of sun and cloud. 10 to 15 km/h southwest ridgetop winds. Treeline temperature -5 °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.
  • Be careful with wind-loaded pockets, especially near ridge crests and rollovers.

Avalanche Problems

Persistent Slabs

Several persistent weak layers exist, with the most problematic ones lying 30 to 60 cm deep. The greatest concern for triggering these layers lies in areas where a thick, supportive crust is absent near the surface.

Aspects: North, North East, East, West, North West.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1.5 - 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: Likely

Expected Size: 1 - 2