Avalanche Forecast
Issued: Dec 28th, 2019 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs and Wind Slabs.
tim haggarty,
Parks Canada
Keep to low angled terrain and avoid exposure to large overhead features. While ski tracks are starting to push out, there is a great deal of uncertainty with the recently overloaded weak layers at the base of the snowpack.
Summary
Weather Forecast
After a clear, chilly overnight period, warm air entered the region today creating mild inversions. Expect an alpine high of -4 for Sunday, again with the potential for inversions, as cloud cover increases and winds diminish. Cloud cover will increase Monday as winds return and snowfall becomes possible late in the day.Â
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. The weak facets sitting above this crust are an 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 24 hrs. Explosive avalanche control at local ski areas today produced a few sz 1 to 2 windslabs in steep, wind loaded areas as has been seen over the last few days.
Confidence
Due to the number and quality of field observations
Problems
Deep Persistent Slabs
The weak, faceted lower snowpack remains stressed by the new storm snow at all elevations. If triggered the deep facets it will result in a very large avalanche. Reports of whumphfing on the basal layer continue as recent as Friday.
- Be aware of the potential for full depth avalanches due to deeply buried weak layers.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Wind effect is evident in the alpine along the divide with areas such as the Wapta looking hammered . While much of treeline seems to have been spared, it would be wise to expect to find slabs in more exposed areas there too.
- Use caution in lee areas. Recent wind loading have created wind slabs.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 29th, 2019 4:00PM
