Regions
Banff Yoho Kootenay.
Its a mixed bag of wind effect and powder at treeline and above. Thursday looks like a nice day but watch for pockets of wind slab or heavy sluffing in very steep terrain.
Weather Forecast
A cold morning (-25C) for Thursday rising to around -10C in the afternoon. It looks to be a clear day with light winds throughout the region. Friday is calling for a small system (only a couple cm of snow) but alpine winds are forecast to be in the strong range from the West before settling down on Saturday.
Snowpack Summary
30 to 50 cm of snow has fallen since Feb 2. Recent new snow has been affected by light to moderate westerly winds. Cold conditions continue promoting faceting of the snowpack. Down 30 to 75cm, Jan 17 surface hoar produces sudden planar shears in isolated locations treeline and below. A weak basal snowpack exists in shallow areas.
Avalanche Summary
A size 2.5 was reported by Sunshine ski hill today. It was a wind slab in the alpine that was 1m deep likely caused by winds from yesterday. Some other loose dry avalanches were noted in the backcountry and numerous wind slabs have been triggered (size 1-2) over the past week.
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.