Regions
Banff Yoho Kootenay.
Watch for wind slabs in exposed terrain on high alpine slopes, especially where they may overly facets. Two storms have formed most of the current snowpack, and it is a very supportive snowpack considering it is only November. Great ski conditions!
Weather Forecast
Alpine temperatures will stay in the -10 to -20C range for Saturday with mainly light W winds. Temperatures will warm up overnight on Saturday but still stay below freezing. Winds will increase Sunday as we switch to more of a westerly flow with light precipitation expected throughout the day.
Snowpack Summary
A field trip in the Lake Louise area today found 80-100cm of supportive snow at treeline. Above treeline there was extensive wind slab development. The wind slabs were not reactive to skier triggering today but are still a concern, especially in thin snow pack areas. This is consistent with other observations. Overall a good early season snowpack.
Avalanche Summary
A couple small wind triggered slides in steep alpine terrain today. Only minor results from explosive testing during the last two days. Avalanche control Wednesday produced wind slab failures up to size 2.5, one size 3 was triggered on Mt. Stephen at 3000m which appeared to initiate near the ground.
Confidence
Due to the number and quality of field observations
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.