Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
Sunday could prove to be a great day for skiing!
Human triggering of persistent weak layers is more likely in areas East of HWY93N and the Lake Louise backcountry compared to areas to the West.
Confidence
High
Avalanche Summary
No new avalanches observed or reported Saturday.
On Friday, a remote wind slab avalanche on St. Nicholas size 2.5 was reported that stepped down to deeper layers and occurred out of steep unsupported terrain.
Snowpack Summary
10-40 cm of snow sits atop crusts on all aspects except north-facing alpine slopes. Windslab can be found on lee aspects. The integrity of the snowpack related to human triggering is based upon the strength and supportiveness of the surface crust. In areas with no surface crust, concern remains due to the weak basal facets, which have plagued the mid and base of the snowpack all winter. Likelihood of human triggering is higher in this region, particularly in Eastern areas
Weather Summary
Saturday night: Cloudy with clear periods and isolated flurries. Precip: Trace. Alpine temps: Low -10 °C. Ridge wind northwest: 15-35 km/h.
Sunday: Sunny with cloudy periods. Alpine temperature: High -6 °C. Ridge wind west: 20-30 km/h. Freezing level: 1900 metres.
Monday: A mix of sun and cloud. Precipitation: Nil. Alpine temperature: Low -6 °C, High 0 °C. Ridge wind west: 20-35 km/h. Freezing level: 2400 metres
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avalanche Problems
Wind Slabs
Strong winds Thursday, Friday and moderate winds Saturday, accompanied by new snow has built wind slabs in lee features in the alpine. Use caution when transitioning from solar aspects (with a crust) to northerly alpine aspects. Dry loose avalanches are possibility as new snow accumulates.
Aspects: North, North East, East, South East, South, West, North West.
Elevations: Alpine.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
A slab up to 80 cm thick sits on the weak facetted lower snowpack. On all but high north aspects, recent sun crusts and the March 27 rain crust cap this slab, providing some security. Use caution in higher, thin snowpack areas or where these crusts are weak or breaking down with heating.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 2 - 3