Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
Temperatures are warming up, but strong West winds will keep things feeling cold on Friday. The incoming storm will all contribute to slab formation on top of our weak snowpack and we are expecting a small natural avalanche cycle at some point in the next few days.
Confidence
Moderate
Avalanche Summary
No avalanches were observed or reported on Thursday.
Snowpack Summary
Overall, the snowpack is shallow and weak with a base of facets and depth hoar. Forecasted snow with warmth and wind will create slabs of varying thickness depending on amount of windloading overtop of this weak base. We expect these to build incrementally starting on Friday as the storm moves in.
Total snowpack depths at treeline range from 60-120 cms.
Weather Summary
A pacific front is approaching bringing wet, warm and windy weather - a much needed reprieve from the frigid temperatures we've been having!
Friday: Low temperatures ~-30 rising to highs near -20 at treeline. Alpine winds will increase to strong from the West. Light snow with amounts up to 5 cm.
Saturday: Low temperatures ~ -20 rising to highs near -10 at treeline. Alpine winds increasing to extreme from the West/ Southwest. Light snow with forecasted amounts ranging from 1-10 cm.
Sunday: Low temperatures ~ -8 rising to -2 at treeline. Freezing level elevation ~ 1500m. Alpine winds decreasing to strong from the West. Light snow with amounts up to 5 cm.
The models vary on total snowfall amounts but anywhere from 5- 25 cm over the period. Models agree on warming temperatures and strong to extreme winds.
Terrain and Travel Advice
- Watch for fresh storm slabs building throughout the day.
- Uncertainty is best managed through conservative terrain choices at this time.
Avalanche Problems
Loose Dry
Forecasted wind and snow will create loose dry avalanches in steep alpine terrain. These may run further than normal due to the weak facetted base and possibly be a trigger for the deep persistent weak layer.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Likely
Expected Size: 1 - 1.5
Wind Slabs
Forecasted wind and snow will build fresh windslabs in alpine terrain. These will grow throughout the day and, if triggered, will likely gouge down to the deep persistent problem.
Aspects: North East, East, South East.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 1.5
Deep Persistent Slabs
The whole snowpack is thin, weak and facetted, but the biggest facets and depth hoar are at the bottom. Forecasted snow, wind and warm temperatures will gradually build a slab over top of this weak layer and at some point over the next few days, we are expecting a small avalanche cycle failing on this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2.5