Avalanche Forecast
Issued: Nov 18th, 2021 4:43PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
Lisa Paulson,
The natural cycle has tapered off, but explosive work today triggered numerous avalanches to size 2.5.
Summary
Weather Forecast
For Friday expect a mix of sun and cloud, with no precipitation, light winds, and highs around -8C. For the weekend, the forecast is for light precipitation 5-10 cm with gusty SW winds and highs around -10C.
Snowpack Summary
Several cm of fresh snow exist over a surface crust (below 2100m). 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
Explosive work around Lake Louise, Sunshine, and on Mt Bosworth produced numerous avalanches today to size 2,5. Most avalanches were windslabs 20-40 cm thick and some failed on the basal facets. It remains likely a person could trigger or remote trigger an avalanche on steeper slopes that have not yet slid.
Confidence
Due to the number and quality of field observations
Problems
Wind Slabs
Reactive windslabs exist in the alpine and down into some tree-line locations. Explosive work triggered numerous avalanches to size 2 on Thursday generally 20-40 cm thick.
- 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. Today and over the past week several avalanches had long propagations and ran far on this layer up to size 3. Be suspicious or steer clear of steeper terrain that has not slid.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 19th, 2021 4:00PM
