Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
The recent wind has created wind slabs, particularly in the alpine. If triggered these slabs will entrain facets as they progress downslope. Approach steep terrain with caution.
Confidence
Moderate
Avalanche Summary
A size 1.5 wind slab was observed in the cliffs above Bow Summit. It is estimated to be between 24 and 48 hours old. Both Sunshine and Lake Louise ski patrol reported triggering hard wind slabs up to 1.5 with explosives.
Snowpack Summary
Wind effect and wind slab development due to variable winds in the past 36 hours. 20-40 cm of recent snow sits over a very weak layer of facets, surface hoar, or sun crust on steep south aspects. 40-80 cm of total snow exists at treeline throughout the region, with up to 120 cm in loaded alpine features.
Weather Summary
On Monday, the region will encounter cooling temperatures into the range of -5 in the valley and -20 at the ridge. Additionally, small amounts of precipitation (4cm) will be accompanied by an increase in the wind from the SW in the strong range.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- If triggered, loose dry avalanches may step down to deeper layers resulting in large avalanches.
Avalanche Problems
Wind Slabs
Variable winds have created wind slabs 15-30cm deep on a variety of aspects. They may be triggered on their own, but have been prone to stepping down to the persistent layer of facets near the ground.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5
Persistent Slabs
Recent snow and wind loading have created slabs over a persistent weak layer of basal facets, buried sun crusts, or isolated pockets of surface hoar. This layer will be around for some time to come.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1.5 - 2.5