Avalanche Forecast
Issued: Feb 25th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
William Lawson,
Parks Canada
Enjoy the great skiing in sheltered areas but use caution in steep wind loaded areas, and make careful route choices in areas with a thin snowpack where the basal weaknesses are more prominent.
Summary
Weather Forecast
A westerly flow will bring partly cloudy skies to the Banff forecast regions on Wednesday as another weak system approaches. We should see periods of flurries through the day with no significant accumulation. Strong westerly winds in the alpine will continue to move snow at ridge tops.
Snowpack Summary
10-20 cm of recent storm snow covers previously formed wind slabs in lee areas, and buried sun crusts on steep solar aspects. The Feb 1 rain crust is down 20-50 cm and present below 1900 m. In thin snow pack areas a dense mid-pack sits over a weak, faceted base. Thick snowpack areas have a denser base with few weaknesses.
Avalanche Summary
Local ski hills reported newly formed windslab isolated to immediate lee slopes off ridge crest. Ski patrol were able to produce size 1 avalanches on this layer with ski cuts.
Confidence
Problems
Wind Slabs
Wind slabs are present in lee areas of the alpine with isolated pockets of wind slab down into treeline. Cornices have grown very large in recent weeks, so watch your exposure to them carefully.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Deep Persistent Slabs
Avalanche activity on the basal facets has slowed down but the weakness in the snowpack remains a concern. These are hard to predict, but are most likely in areas with a thin snowpack (<150cm) where the basal facets and depth hoar are prominent.
- Use caution in thin snowpack areas.
- Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 26th, 2020 4:00PM
