Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
Strong to extreme winds with new snow will keep the avalanche hazard elevated. An avalanche cycle in the alpine is possible early Monday, depending on new snow amounts.
Avalanche control will take place Monday, Feb 13 on Mounts Field, Stephen and Dennis in Yoho National Park. No activities on these peaks for the day.
Confidence
Moderate
Avalanche Summary
A busy 24 hours for avalanches. Bourgeau Left hand slid naturally (size 3) in the last 24 hours, and explosive control triggered wind slabs to size 2. A MIN report from Saturday of a remote-triggered slide with wide propagations in the Sunshine backcountry. A visitor safety team also triggered a healthy size 2.5 (80 wide) at 2400m on observation glades on Sunday.
Snowpack Summary
Up to 30cm of recent storm snow in the North (10cm in the South) of the region has been redistributed by strong winds forming widespread, reactive windslabs. Two crusts exist in the upper snowpack and the November facets remain near the base. These buried weak layers remain a concern and continue to produce avalanches. Minimal reactivity has been observed below treeline.
Weather Summary
Strong to extreme alpine SW winds can be expected overnight into Monday (70-90km/h). North of Lake Louise 15-20cm is possible, with lower amounts to the East. Snow will taper by the afternoon as winds die down. Freezing levels will remain at valley bottom and alpine temperatures -3 to -9C. Cooler temperatures and light winds for Tuesday.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Make conservative terrain choices and avoid overhead hazard.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avalanche Problems
Wind Slabs
These slabs are sensitive and can be easily triggered by humans. In many areas these wind slabs overlay a variety of surfaces like crusts and facets. Incoming wind and snow will add to this problem. There have been reports of many avalanches related to this over the past 24 hours.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Very Likely
Expected Size: 1 - 2.5
Deep Persistent Slabs
Natural and human-triggered avalanches are still occurring on the basal facets and depth hoar. They are either initiating on this layer or more frequently initiating as a wind slab which steps down.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1.5 - 3.5