Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
With clear skies and warm temps, be mindful of the potential for wet loose avalanches out of steep solar aspects.
Some fresh wind-slabs can be expected in immediate alpine lees.
Keep the deep persistent layers in mind, especially on large alpine slopes.
Confidence
Moderate
Avalanche Summary
Lake Louise ski hill had a few explosive results Wednesday during avalanche control operations. Mainly no results but some size 1 wind-slabs on NE aspects in the alpine with one more significant result with an larger explosive trigger size 1.5 on a deeper persistent weak layer.
Sunshine ski hill reported some solar triggered natural size 1's out of steep rocky terrain at ridgetop.
Snowpack Summary
The early-season settling snowpack at treeline measures 50-90 cm. In the alpine there is scouring on windward slopes and some fresh loading on immediate lee aspects. A surface crust or moist snow may exist on steep south aspects below 2500m. The November crust lies mid-pack on south aspects, while the main concern is the October crust near the ground on north aspects, where facets and depth hoar are forming. The snowpack is generally weak and facetted.
Weather Summary
Freezing levels Thursday will continue to climb (up to ~1900m) as there will be reduced cloud cover and a warm air mass moves into the region. Winds will continue to be moderate to strong from the west. Friday temps will cool with some forecasted precipitation Saturday.
Terrain and Travel Advice
- Rocks will heat up with daytime warming and may become trigger points for loose wet avalanches.
- Pay attention to the wind; once it starts to blow, sensitive wind slabs are likely to form.
- Be mindful that deep instabilities are still present in the snowpack.
Avalanche Problems
Deep Persistent Slabs
The October and November crusts, on north and south aspects respectively, are still producing isolated slab avalanches down about 50-80 cm. Be mindful on steep, rocky alpine slopes where triggering is most likely.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1.5 - 2
Wind Slabs
Recent moderate to strong winds have formed wind slabs on lee slopes in the alpine. If triggered, these slabs could entrain facets, leading to longer-than-expected runouts.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 1.5