Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
More snow and wind will keep the avalanche hazard elevated this weekend. A deep freeze is on its way with temperatures dropping down to the - 30s by Sunday. Be prepared for the unexpected with extra warm clothing.
Confidence
Moderate
Avalanche Summary
Over the past few days, both ski hills have triggered deep slabs up to size 2 with explosives or sometimes with a ski cut after the explosive failed to trigger the slope. Parks Forecasters have noted large whumphs in the Sunshine Backcountry on Tuesday and in the O'hara region on Thursday. No new naturals have been observed for the past few days.
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. Snowpack depths at treeline range between 60 and 120 cm. Below treeline, small sluffs may be triggered in steep features where the ski and foot penetrations are to the ground in a very weak facetted snowpack,
Weather Summary
A surface ridge of high pressure will continue to push moist air South causing upslope conditions on the Eastern slopes of the Rockies. We could see up to 10cm of low-density snow in the forecast region by Sunday. The temperature will drop through the day Saturday with alpine lows temps to -30. Increased winds and new snow will add to the loading in the alpine , likely developing new slab at upper elevations.
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.
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. Below treeline, the snowpack is very weak and unsupportive.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2.5
Wind Slabs
Forecasted snow amount of up to 10cm and Moderate to Strong alpine winds Saturday could developed new Wind Slab at upper elevations. These new Wind Slabs will likely be isolated to immediate lee slopes.
Aspects: North East, East, South East, South, South West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 1.5
Loose Dry
Cold temps and a thin snowpack have resulted in significant faceting at lower elevations. On steep sheltered slopes the snowpack has very little structure. Its possible for skiers to initiate loose snow, resulting in a loose dry avalanche where the terrain is steep enough.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5