Avalanche Forecast
Issued: Nov 20th, 2021 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,
Strong to Extreme winds have added more loaded to the existing problems in the snowpack. We continue to receive isolated report of large destructive avalanches.
Summary
Weather Forecast
Light precipitation forecasted for Sunday with snow accumulation amount between a trace to 5cm. Slight decrease in upper elevation winds for Sunday will be short lived as strong to extreme values return on Monday. Freezing levels will stay near valley bottom.
Snowpack Summary
Several cm of fresh snow exist over a surface crust (below 2000m).Last weeks storm snow (5 day total of 65-90 cm) continues to settle. Wind slabs exist in alpine and down into tree-line elevations. A melt/freeze crust and/or facets exist near the ground (in some locations). Snowpack depths at tree-line average 60-110 cm
Avalanche Summary
We received a report of one large size 2.5 natural avalanche observed in the Lake Louise area from the past 24 hours. This slab release was likely initiated from wind loading. local ski hills continue to report avalanches to size 2.5 triggered with explosives.
Confidence
Problems
Wind Slabs
Reactive windslabs exist in the alpine and down into some tree-line locations. We observed active wind loading through the day Saturday as strong to extreme winds striped windward slopes.
- Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.
- Use caution in lee areas. Recent wind loading have created wind slabs.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A facet or facet crust layer exists at the bottom of the snowpack. Although natural avalanche activity has decreased on this layer we continue to receive report of human triggering. Be suspicious or steer clear of steeper terrain that has not slid.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 21st, 2021 4:00PM
