Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
Small wind slabs on the immediate lee of alpine ridges and features linger as a concern. 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
No Rating
Avalanche Summary
No new natural avalanches were reported today. A spike in wind on Saturday resulted in numerous reports of wind slab avalanches (size 1 to 1.5) failing on the Feb. 3 crust. 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 48 hours.
Snowpack Summary
Wind slabs have formed in lee areas of the alpine with west winds over the weekend. At treeline, 10-25 cm of recent storm snow sits over the Feb 3 crust. The Feb 3 crust is present on all aspects except north above 2500 m and ranges from 1-15 cm thick, with the thickest found in Yoho. Mid-pack persistent 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 night: NW wind 20-30 km/hr no snow and increasing clouds through the night.
Tuesday: Cloudy skies in the morning with 2-4 cm along the Eastern part of the region. As a high-pressure system builds, skies will clear through the remainder of the day, winds will become light, and temperatures will drop with overnight lows dipping to -18C on Wednesday night.
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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 WSW winds moved the 10-25 cm of low-density storm snow around to form wind slabs in lee 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.
Likelihood: Possible
Expected Size: 1 - 2
Persistent Slabs
The persistent weak layers in the mid-pack down roughly 30 and 50 cm remain a concern. Sporadic activity has occurred on these and, in isolated events, has scoured 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