Regions
Banff Yoho Kootenay.
The main concerns right now are small buried wind slabs and sluffing in steep terrain. We have removed the persistent slab problem because of a lack of activity on this layer, but the structural weakness remains and the problem may show up again.
Weather Forecast
Temperatures should cool on Friday while the winds remain light from the East. About 5cm of new snow is expected Friday with an additional 5 cm on Saturday and continued light winds and cool temperatures.
Snowpack Summary
A few cm's of new snow Thursday with light E winds. Buried wind slabs exist in most open areas at higher elevations, with loose surface facets at lower elevations. Three mid-pack weak layers of surface hoar and/or facets down 100-130 cm appear well bonded, but are worth checking on bigger slopes. Recent tests are showing no results on those layers.
Avalanche Summary
Small explosive triggered wind slabs were reported at local ski areas Thursday, with the debris entraining surface facets. Surface sluffing was also reported in steep treeline areas in Kootenay. We have not seen any avalanche activity on the persistent layers for about ten days and have removed this as a problem but the structural weakness remains.
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.