Avalanche Forecast
Issued: Nov 19th, 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 are forecasted for Saturday. This will likely increase the avalanche activity at upper elevations.
Summary
Weather Forecast
Light precipitation beginning Saturday will bring up to 10cm of snow to the forecast region by the end of the weekend. Strong to Extreme winds are expected at mountain top Saturday. Temperature will gradually rise this weekend with freezing levels hovering near valley bottom by Sunday.
Snowpack Summary
Several cm of fresh snow exist over a surface crust (below 2000m). Recent storm snow (5 day total of 65-90 cm) is settling. 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
Natural avalanche activity has decreased but we continue to receive report of human triggered avalanches in the region. Lake Louise ski patrol reported a remotely triggered size 2 avalanche that released on a weak layer at the bottom of the snowpack. We expect natural avalanche activity to increase with strong to extreme winds in the forecast.
Confidence
Problems
Wind Slabs
Reactive windslabs exist in the alpine and down into some tree-line locations. We expect this avalanche problem to become more reactive over the weekend as upper elevation wind values increase to strong-extreme range.
- 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 20th, 2021 4:00PM
