Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
Consequences are still high if you trigger a deep persistent slab. Be prepared to make conservative route choices for the foreseeable future. See snowpack observations at Bow Summit today.
Confidence
Low
Avalanche Summary
Lake Louise patrol was knocking out hard wind slabs with explosives, that would gauge down to the ground and entrain facets. These slides were size 1.5 and all occurred in the alpine. Sunshine patrol was able to trigger one size 2 deep slab in previously uncontrolled terrain with explosives. As usual, it entrained facets as it progressed downslope.
Snowpack Summary
20-60 cm of snow has formed a slab over a very weak base consisting of facets. Thin crusts can be found on the facet interface at lower elevations and on solar slopes. Expect to find lingering wind slabs at higher elevations. Snowpack depths at treeline range between 60 and 120 cm.
Weather Summary
Relatively warm valley bottom temps of near zero, with the alpine around -10 on Wednesday. A small amount of precipitation is expected overnight Tuesday into Wednesday (2-4cm), Wind is expected to remain light from the NW on Wednesday. Overall, a benign weather pattern will persist with minimal inputs to the snowpack.
Terrain and Travel Advice
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- Uncertainty is best managed through conservative terrain choices at this time.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avalanche Problems
Deep Persistent Slabs
A 20-60 cm slab has formed over the very weak basal facets, with thin crusts at the interface at lower elevations and on some solar slopes. Human triggering is likely on any steep slopes where a cohesive slab of snow is found. This problem will remain for the foreseeable future.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1 - 2.5
Wind Slabs
10-25 cm of snow fell over the past week and moderate S-W winds formed wind slabs in lee areas. These slabs are relatively small but the major concern is that if triggered, these may step down to the weak basal facets resulting in larger avalanches.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2