Regions
Banff Yoho Kootenay.
Some snow and wind are still forecast for Friday night. Watch local accumulations as this will dictate a rise in hazard at all elevations.
Weather Forecast
We still expect snow up to 20cm in the alpine Friday night with the highest amounts along the divide and especially the Wapta. Expect strong SW winds over all regions. Another system is forecast on Sunday night. Steep areas below treeline and treeline W of the divide may go above a low hazard rating with a bigger snow load.
Snowpack Summary
2-9cm reported over last 24 hours in alpine regions. Some thin wind slab formation in immediate ridge top lees This snow sits on top of previous wind slabs, both soft and hard, in alpine areas. Thin snowpack areas at all elevations are very weak and faceted, as well as most below treeline areas up to around 1900 meters.
Avalanche Summary
No activity reported today. Avalanche control on Wednesday produced avalanches up to size 3. Cornices that were triggered provided enough of a rake to entrain all of the facets in the path, running to within 100m of the road on Mt. Whymper (Kootenay) and Mt. Dennis (Yoho).
Confidence
Forecast snowfall amounts are uncertain on Saturday
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.