Regions
Banff Yoho Kootenay.
Watch for the bond between wind slabs and loose powder to harder bed surfaces below before stepping into steep alpine terrain features. Expect some sun Wed. so watch for increasing hazard in the afternoon. SH
Weather Forecast
Moderate gusting strong NW winds at ridgetop Wed. with good overnight recovery expected and no new snow. We may see a jump in hazard on Friday due to strong winds and possibly some new snow West of the divide.
Snowpack Summary
Cool and mainly cloudy conditions kept crusts intact today into the afternoon. Wind slabs can be found in steep alpine features, especially near ridge crests.. These slabs can be triggered on all aspects, especially S where they overly harder crusts. Loose snow avalanches on N aspects over harder bed surfaces in the alpine were seen Tuesday.
Avalanche Summary
A field team saw heavy sloughing with ski cutting in a steep North aspect (2800m) in the Lake O'hara region. This was overlying a harder bed surface. Numerous other avalanches to size 1.5 have been observed in steeper terrain, especially on Southerly aspects.
Confidence
Due to the number and quality of field observations on Wednesday
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.