Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
Natural activity has tapered since the large avalanche cycle this past week. However, human-triggered avalanches are still likely.
Confidence
Moderate
Avalanche Summary
We have just come out of an avalanche cycle to size 4 which had many full-depth avalanches that ran a long way. Avalanche control Thursday on Mt. Bosworth produced avalanches up to size 2.5. On Wednesday in Kootenay, avalanche control produced slides to size 3.5 with very wide propagations. Sunshine ski hill got a number of size 2.5 avalanches on the basal layers with explosive control.
Snowpack Summary
Recent storm snow has settled to around 30cm above 2300m. This lies over previous surfaces such as sun crusts up to ridge top and faceted layers on shady aspects. Below 2300m, surface crusts lie over a fairly isothermal snowpack due to previous rain.
Several buried crusts are in the top 50-60 cm on solar aspects. The bottom of the snowpack remains facetted and weak.
Weather Summary
Friday: As the day warms up expect convective flurries up to 5cm in some locations along the front ranges. Winds will be light from the East with freezing levels 1700-1900m.
Saturday: Starting sunny and clouding over in the afternoon. Winds will be increased from the SW and freezing levels to 2000m.
Avalanche Problems
Storm Slabs
30-40cm of storm snow fell this past week in a big storm. These formed widespread storm slabs in alpine and tree-line areas, which will still take some time to settle. The big worry is if they are initiated, they may step down to the deeper layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2.5
Deep Persistent Slabs
The November basal facets (as well as midpack facets on crusts) remain a significant concern. The recent avalanche cycle shows how large these can be once initiated. Natural activity has tapered overall, but human triggering is still likely.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 2 - 4
Loose Wet
Freezing levels to 1900m with some sun will mean an increase in avalanche danger as the day warms up. This will be especially the case in steep terrain around rocky features.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 2