Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
The weather has changed and so has the hazard. Be mindful of increased wind loading.
The more snow we receive Sunday, the more the hazard will increase along with a higher likelihood of triggering the deeper weak layers.
Ice climbers watch for loose dry avalanches.
Confidence
Low
Avalanche Summary
Numerous dry loose avalanches up to size 1.5 out of steep terrain have been reported over the last 24 hours from the Lake Louise and Field areas.
A group in Surprise Pass reported a size 1 wind slab at tree line.
No other avalanches were reported.
Snowpack Summary
Recent strong winds and new snow have resulted in widespread wind effect at ridgetop and below, creating windslab on lee aspects. In sheltered areas, 15-35 cm of predominantly new and old facetted snow overlies the Feb 3 crust on all but N aspects above 2500m. In shallower snowpack areas, weak facet layers can be found in the mid and lower snowpack. Thin snowpack values overall this year in this sub region with around 130 cm at 2000m.
Weather Summary
A low-pressure system will develop in the lee of the Rockies. This system will produce flurries accumulating 5-10 cm. Freezing levels 1600-1900 m. Strong to extreme southwest winds at ridgetop. Additional snowfall amounts of 4-8 cm will accumulate overnight into Monday morning.
Temperatures will cool and winds will abate Monday.
For more information see AvCan's Mt Wx
Terrain and Travel Advice
- Watch for signs of slab formation throughout the day.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Avalanche Problems
Wind Slabs
Expect to find wind slabs in alpine lee terrain, possibly down into treeline. These slabs generally overlie faceted snow and/or a crust. As strong southwest winds continue through Sunday, expect incoming snow amounts of 5-15cm and mild temperatures to contribute to slab development.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Loose Dry
Strong to extreme winds are causing wind loading and spind drift avalanches in steep terrain. Ice climbers should be particularly attentive to this problem and avoid lee aspects with overhead hazards.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1.5
Deep Persistent Slabs
Weak facet layers exist in the mid-pack as well as at the bottom of the snowpack. Sporadic avalanche activity continues on these layers mainly in thin snowpack, rocky, and steep locations, and with increased load, these may become more reactive. Use extra caution when the Feb 3 crust becomes thin.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 2.5