Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
We continue to have skier triggered avalanches and large whumpfs on the deeper weak layers in the snowpack, especially in thin snowpack areas. Moderate terrain choices with minimal overhead hazard continue to be a good idea for dealing with a weak snowpack like this.
Confidence
Moderate
Avalanche Summary
We continue to see skier, natural and explosive triggered avalanches. A size 3 skier triggered avalanche was observed on an east aspect of Mt. Fairview failing on the basal facets, and a smaller skier triggered slab was observed on Lipalian on Sunday. Several naturals to size 2 were observed including cornice failures in the past 48 hrs, and explosive control at local ski areas produced slabs up to size 2.5 with some stepping down to the basal facets.
Snowpack Summary
Alpine and exposed treeline areas are wind effected with wind slabs that are slowly becoming less reactive. Steep solar slopes at treeline and below have a thin sun crust. The the various Jan PWL interfaces of sun crusts, facets, and surface hoar are now down 40-80 cm. The weaker Nov. 16 basal facet layer is down 50-120 cm and produces moderate to hard sudden collapse results in tests.
Weather Summary
A stable weather pattern continues with treeline highs of -8°C and overnight lows of -20°C. Winds will be calm to light from the W/SW. The skies will be mostly clear with some scattered clouds.
For a more detailed weather forecast, click here.
Terrain and Travel Advice
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avalanche Problems
Deep Persistent Slabs
Weak facets and depth hoar are present at the bottom of the snowpack which inspires little confidence. Be especially cautious in thin snowpack areas, which are likely areas for triggering.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1.5 - 3
Persistent Slabs
Three persistent weak layers formed in January are down 40-80 cm. The biggest concern is triggering these buried suncrusts on steep solar slopes, but weaker facets and isolated surface hoar can be found at the same interfaces on shaded aspects.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1.5 - 2.5
Wind Slabs
Windslabs from last weeks storm have been buried by low density snow and are gradually becoming less reactive.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2