Avalanche Forecast
Regions: Banff Yoho Kootenay.
With winds forecast to increase late Monday and some potential for snow, be wary of the potential for an up-tick in natural activity into Tuesday. Continue to avoid exposure to overhead avalanche terrain and select modest angled slopes for travel.
Weather Forecast
Cloud cover will increase Monday as warmer air approaches. A mild inversion may remain until midday as winds rise to strong in the alpine, possibly arriving with small amounts of snow. Into Tuesday, and through Wednesday, a series of systems will reach the forecast region with light snowfall. Winds look like they will diminish late Tuesday.
Snowpack Summary
Moderate to strong W and SW winds have redistributed snow in the alpine and the upper areas of treeline. Snowpack depths at treeline range from 100 to 160cm. The Nov crust is found ~ 30cm above the ground and is present up to 2500m. Weak facets below this depth are the obvious weakness and are more developed in shallow areas.
Avalanche Summary
Recent reports of skier triggered avalanches within the region and reports of whumphfing on the deep persistent layer have continued in the last 48 hrs. Explosive avalanche control at ski areas today produced a few sz 1-2 windslabs in steep, wind loaded areas as has been seen over the last few days with a few of these stepping down to the facets.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Tuesday
Avalanche Problems
Deep Persistent Slabs
The weak, faceted lower snowpack was heavily loaded by the storm before Christmas . Triggering the deep facets would result in a very large avalanche. Continued reports of whumphfing on these basal layers indicate the potential for human triggering.
- Be aware of the potential for full depth avalanches due to deeply buried weak layers.
- Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 3.5
Wind Slabs
Wind effect is evident in the alpine as a result of winds over the previous 3-4 days. Be wary of the potential to trigger even a small slab given the possibility of triggering the deeper weakness as an avalanche starts to increase the load on a slope
- Use caution in lee areas. Recent wind loading have created wind slabs.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2