Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
The avalanche hazard has increased slightly with new wind slabs and sluffing in steep alpine terrain features. Some weaknesses persist in the mid and lower snowpack, and while reactivity of the lower layers has been limited, avalanches are still possible. Keep this in mind if entering steep committing terrain.
Confidence
High
Avalanche Summary
There are numerous reports of new wind slabs over the Feb. 3 crust causing avalanches (size 1 to 1.5) at treeline and above. Also, there were a couple of deeper and larger releases, mainly on the mid-pack facets, but also a deeper one to ground in steep terrain on Fairview in the last 24 hours.
Snowpack Summary
Wind slabs have formed in lee areas of the alpine with increased west winds and some sluffing in steep terrain. 10-25 cm of recent storm snow sits over the Feb 3 crust that is present on all aspects except north above 2500 m. This crust ranges from 1-15 cm thick, with the thickest found in Yoho. Mid-pack weak layers from Jan and Dec are down roughly 30 and 50 cm respectively. Facets and depth hoar make up the basal layers of the snowpack in most locations.
Weather Summary
Monday: Cloudy with trace amounts of snow East of the divide and 2cm West of the divide, alpine winds 25-35kmh switching from West to NW and valley bottom freezing levels
Tuesday: Partly cloudy, no snow, light N/NW winds, and valley bottom freezing levels.
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Terrain and Travel Advice
- Wind slabs may be poorly bonded to the underlying crust.
- Watch your sluff: it may run faster and further than you expect.
- Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
Avalanche Problems
Wind Slabs
Recent winds have moved the 10-25 cm of low-density storm snow around, forming wind slabs in alpine areas. This new snow sits on the Feb 3 crust, and any slab or sluff will likely travel far and fast in steep terrain features.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Persistent Slabs
Persistent layers from mid-January and the end of December exist in the mid-pack down roughly 30 and 50 cm. Sporadic activity has occurred on these and, in isolated events, can scour down to the basal facets. This should be considered in more committing terrain.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 3