Avalanche Forecast
Regions: Banff Yoho Kootenay.
With a warm blustery storm Friday, we are now starting to see small slab avalanches reported into treeline. As another storm arrives Saturday night expect avalanche hazard to rise rapidly.
Weather Forecast
Expect winds to shift NW overnight Friday as temperatures fall to -5C at 2000m. Light snowfall is expected to continue Saturday morning. A second system looks to arrive Saturday night with up to 20cm expected through the day Sunday and up to 50 by Tuesday. Expect freezing levels to approach 2000m and Westerly winds to approach 60 kph in the alpine.
Snowpack Summary
Mod- Strong SW winds brought 2-5cm of snow Friday with rain below 1800m. Previously 20-30cm of recent snow had been deposited on a thin melt-freeze crust thought to exist as high as 2500m. Below this crust is 10-30cm of facetted snow that sits on 5-10cm of melt-freeze crystals at or near the ground. 30-50cm of snow at treeline, more into the alpine
Avalanche Summary
We have very limited observations - thank you for the MIN reports! Over the last few days, Lake Louise and Sunshine have reported triggering windslab avalanches up to size 1.5, on average 40 cm deep running on the ground. A few more small slabs were reported into treeline elevations with rapid loading Friday.
Confidence
Avalanche Problems
Wind Slabs
Although small, these avalanches could give someone a rough ride through the rocks. The most attractive slopes to ride may be where this problem exists. Overhead cornice failure triggered by increased wind may trigger windslab pockets below.
- Use caution in lee areas in the alpine. Recent storm snow has formed wind slabs.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Loose Dry
Snow with moderate to strong winds Friday and overnight into Saturday has likely set us up for small sluffs to be spilling off of steep terrain Saturday. Climbers should consider these as a factor in their route selection.
- Be careful of loose dry sluffing in steep, confined or exposed terrain.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1.5