Avalanche Forecast
Regions: Banff Yoho Kootenay.
Recent new storm snow, warming temperatures and wind from the south west have contributed to deteriorating conditions. Wind slabs in the alpine and at treeline will be primed for human triggering on Sunday.
Weather Forecast
Warming temperatures (-5 valley; -8 ridge) and strong to extreme wind from the SW overnight on Saturday into Sunday. Minimal amounts of new snow are expected.
Snowpack Summary
15-30cm storm snow with winds strong out of the S-SW. Wind slabs building at treeline and in alpine areas as that loose snow gets blown around. These slabs may bond poorly to the underlying facets from the cold snap. The Dec 2 crust/facet interface is down 60-100 cm, and the snowpack is very faceted in shallower areas.
Avalanche Summary
Lake Louise patrol triggered wind slabs up to size 2 with explosives, up to 40cm deep. Additionally they were able to ski cut small size 1 loose dry avalanches at treeline. Two small size 1 avalanches were observed near Serac Creek in Kootenay. It appeared to be a steep side wall gully. Approx. 40cm deep and 20m wide.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Sunday
Avalanche Problems
Wind Slabs
Moderate SW wind has been loading lee areas in the alpine and tree line on Saturday afternoon. This, coupled with a slight rise in temperature will increase the likelihood of human triggering.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2.5
Loose Dry
New snow, wind and a faceted snowpack will combine to increase the likelihood of loose dry avalanches in steep terrain on Sunday. The loose dry avalanches are not expected to be big, but limit your exposure to terrain traps.
- Good group management is essential to manage current conditions safely.
- On steep slopes, pull over periodically or cut into a new line to manage sluffing.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 1.5
Persistent Slabs
The Dec. 2 crust/facets are down 60-100 cm throughout the region, but we have seen limited avalanche activity on this layer. It has mainly been a problem in Kootenay, but there is a high degree of uncertainty around this layer as we get more loading.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1 - 2.5