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 Persistent Slabs and Wind Slabs.
Garth Lemke,
The Forecast team considers the likelihood of triggering is going down but the consequence is severe if anything is triggered. As Senior Forecaster Cory Boschman says "ski lightly and think conservatively".
Summary
Weather Forecast
Saturday will be cloudy and flurries, 4 cm of snow, -9 degrees and 20 km/h gusting to 60 km/h W to SW winds. Sunday will be similar to Saturday with less winds. The sun may poke out on Monday and no new snow is expected.
Snowpack Summary
Surface hoar is forming up to 4mm on the 60-80cm of storm snow that fell Nov 13-15th. The storm snow has settled into a persistent slab particularly where the wind has influence. A 2cm thick crust 80cm down is found up to 2500m or higher. Weak facets are below the crust resulting in sudden collapse test results. This should cue you to be cautious.
Avalanche Summary
Friday's team observed two size 2 persistent slab avalanches on windloaded features in the alpine and treeline. On Wednesday numerous avalanches up to size 3.5, generally from steep alpine features, were noted. They occurred during or at the end of the Nov 13-15th storm. One 800m wide avalanche was caused by explosives at tree-line on Tuesday.
Confidence
Wind effect is extremely variable on Saturday
Problems
Persistent Slabs
60-80cm of storm snow from Nov 13-15th has settled into a persistent slab condition. Field tests are showing sudden collapse on a crust down 50-80cm over weak facets. The snowpack arrived only four days ago and the prudent thing to do is be cautious.
- Avoid thin rocky or unsupported terrain features.
- Use caution on open slopes and convex rolls
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Watch for wind loading at ridge tops and in the alpine with recent moderate West and SW winds. Winds may increase to 75km/hr on Saturday and there is a lot of snow available for transport.
- Use caution in lee areas. Recent wind loading have created wind slabs.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 20th, 2021 4:00PM
