Regions
Banff Yoho Kootenay.
2 storms have formed most of the current snowpack, and its a very supportive snowpack considering its November. Watch for wind slabs in exposed terrain on high alpine slopes, especially where they may overly facets. Great ski conditions. SH
Weather Forecast
Alpine temperatures will stay in the -15 to -18C range for Friday, with mainly light N to NW winds and only trace amounts of snow. Temperatures will warm over the weekend with a slight temperature inversion , but still staying below freezing. Winds will also increase over the weekend as we switch to more of a westerly flow.
Snowpack Summary
A field trip to Kootenay today found 80cm of supportive snow at treeline, A profile at 2200m found a 1 finger snowpack under the latest storm snow, and rounded facets at the base. Exposed areas have wind slab development, and thinner alpine areas have a facetted base. This is consistent with other observations. Overall a good early season snowpack.
Avalanche Summary
Avalanche control yesterday produced results up to size 2.5, which were wind slabs. One size 3 was triggered on Mt. Stephen at 3000m which appeared to initiate near the ground. Many produced no result. There was a surprising lack of activity with extensive flights over the region, and little wind effect except in alpine regions.
Confidence
Due to the number of field observations on Friday
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.