Avalanche Forecast
Issued: Feb 1st, 2022 4:50PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Wind Slabs and Persistent Slabs.
Brian Webster,
Touchy storm slabs that sit on a well preserved surface hoar layer are the biggest concern right now.
Summary
Weather Forecast
Cold air will continue through Wednesday and then start to warm up on Thursday. Valley bottom temps on Wednesday in Lake Louise will be -15. Flurries forecast for Thursday, but little accumulation. Ridgetop winds will pick up Wed afternoon into the mod to strong range.
Snowpack Summary
15-35 cm storm snow has created fresh windslabs in the alpine. Storm slabs exist at tree-line and below treeline elevations where storm snow sits on a touchy surface hoar layer. This was very apparent on Mt Field on Monday but this problem is expected to exist in other areas within the forecast region. Expect easy triggering of these soft slabs.
Avalanche Summary
Field team to Mt Field on Monday experienced numerous ski-cut and natural avalanches on the storm snow interface down 25-35 cm. The storm snow was sitting on a 3-5 mm well preserved surface hoar layer. Ski hills reported several small natural and explosive triggered windslabs in the alpine.
Confidence
Wind speed and direction is uncertain on Thursday
Problems
Storm Slabs
There is a touchy storm snow interface, down 15-35 cm, on surface hoar/crust/facets buried on Jan 30. Steep rolls with >20 cm of snow are most reactive, if they have not already slid.
- Convex features and steep unsupported slopes will be most prone to triggering.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Wind Slabs
New windslabs have formed in the immediate lees of features and are up to 40 cm deep.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
This problem represents both the Dec. 2nd crust/ facet layer (treeline and below) and the late December facet layer. Lots of variation in the sensitivity ranging from reactive sudden collapse to no results depending on location, aspect and elevation.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 2nd, 2022 4:00PM
