Avalanche Forecast
Regions: Banff Yoho Kootenay.
Despite the cold temperatures avalanches continue to occur daily. As temperatures slowly increase there is some potential for the frequency of this activity to increase as well.
Weather Forecast
Winds have returned to the SW and have backed off to generally light where they should remain Monday. Alpine temps reached -20C today but are expected to peak at -15C Monday while valley bottom temps may break -10C with clear skies to start the day. Increasing cloud late Monday may lead to trace amounts of snow overnight and cooling in the alpine.
Snowpack Summary
Winds have created small slabs in lee areas of the alpine, and wind effect into open areas at treeline. The surface snow is facetting and beginning to sluff more easily in steep terrain. A facet layer from Jan 27th is present at treeline and in the alpine down 30-40cm. On steep south this layer may consist of a thin sun crust as well.
Avalanche Summary
Several cornice failures have been observed over the past few days including one on Fatigue Mountain today that triggered a size 3 on the ground reminding us that there is still a deep layer. Forecasters ski cut a size 2 in the Simpson area at 2100 m on the persistent layer saturday. SSV reports working with small stubborn windslabs in the alpine.
Confidence
Due to the number of field observations
Avalanche Problems
Wind Slabs
Recent variable winds have built slabs. These are mainly small in size but would be of concern in steep alpine terrain. There have also been several examples of cornice failures over the last few days creating larger events that involve these slabs.
- Use caution in lee areas. Recent wind loading has created wind slabs.
- Pay attention to overhead hazards like cornices which could trigger slabs.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2
Persistent Slabs
Continued observations of isolated avalanches near treeline over the last two weeks, mainly centered around the Kootenay region. These are 30-40 cm soft slabs over the Jan. 27 layer : facets, or facets over a thin sun crust on steep south aspects
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2
Loose Dry
As the surface snow facets and weakens, it is starting to sluff more easily in steep terrain. This is mostly a problem in narrow confined terrain like gullies or couloirs.
- On steep slopes, pull over periodically or cut into a new line to manage sluffing.
- Consider that avalanches may run further than expected as they entrain this loose surface snow.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5