Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
Heavy snowfall has resulted in over 50 cm of new snow, with more expected, in the northern part of the forecast region. The avalanche danger is expected to remain HIGH over the next few days as the snowpack adjusts to this new load.
In areas with higher snowfall amount, we advise backcountry users to avoid avalanche terrain.
Confidence
High
Avalanche Summary
The forecast team did not make any new avalanche observations on Sunday due to limited visibility along Highway 93N. We expect an ongoing natural avalanche cycle in the northern parts of the forecast region, where heavy snowfall has deposited over 50 cm of snow in the last 24 hours.
In areas with higher snowfall amounts, we advise backcountry users to avoid avalanche terrain as the snowpack adjusts to this new load.
Snowpack Summary
New Snow amounts varies significantly, with over 50 cm in the north and as little as 10 cm in the south and east. The storm snow is settling quickly and developing into a slab, and at upper elevations being transported by strong winds. This overlays crust on Southerly aspects.
A Persistent weak layers of mainly facets (Feb. 22nd / Jan. 30th) exist 80cm down. In thin areas to the east, basal facets linger at the base of the snowpack.
Snow depth at tree line ranges from 80cm to 180cm
Weather Summary
An atmospheric river will continue to bring heavy snowfall to the region Sunday night. This system has primarily affected the northern parts of the region. Snow amounts so far ranges from over 50 cm at Bow Summit to 10 cm in the Simpson area. An additional 20 to 30 cm of snow is possible Sunday night before conditions begin to clear. Winds will start to decrease Monday, and freezing levels will drop to valley bottoms.
Terrain and Travel Advice
- Avoid avalanche terrain during periods of heavy snowfall.
Avalanche Problems
Persistent Slabs
Over the past week, numerous avalanches have occurred on these layers (30-80cm deep). With the new snow overloading the snowpack, the likelihood of both natural and human-triggered avalanches will rise.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1.5 - 3
Storm Slabs
The storm has deposited over 50cm of snow in the northern part of the region with more to come Sunday night. Heavy snow fall, warmer temps, and strong to extreme winds are contributing to storm slab development. Where higher storm snow amount exist we expect this problem to be very reactive.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Certain
Expected Size: 1.5 - 2.5
Deep Persistent Slabs
A lingering basal weakness could wake up as the storm snow over loads the snowpack. We expect the problem to be mainly a concern in shallower snowpack areas in the eastern part of the region.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3