Regions
Banff Yoho Kootenay.
Avalanche hazard will begin rising as the new snow arrives on Sunday afternoon and Monday. Keep a close eye on local snowfall amounts and winds. CJ
Weather Forecast
Moderate snowfall is forecast to begin by mid-day on Sunday with 5-10cm of new snow by Sunday evening accompanied by strong West winds. An additional 5-10cm is forecast for Monday before the cold, dry arctic air arrives on Tuesday.
Snowpack Summary
On lee features in the alpine the snowpack consists of wind slabs over a weak mid-pack with a very weak base of facets. The Oct 27 crust on N-NE aspects in the alpine is breaking down, but is still a sliding layer near ground. On average at treeline there is 70 cm of snow, barely blanketing the rocks and stumps.
Avalanche Summary
No new avalanche activity over the last 48 hours. Expect sluffing to begin as the new snow arrives on Sunday.
Confidence
Intensity of incoming weather systems is uncertain
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.