Regions
Banff Yoho Kootenay.
Cooler temp's will help bring the danger levels down, but it will take a few days for the new snow to stabilize at all elevations. Use conservative terrain choices.
Weather Forecast
The snow will ease off tomorrow and we should see freezing levels drop to 1200m by the end of the day. Winds will also decrease to moderate from the west. We may even see broken, patchy clouds east of the Divide. Saturday may bring another disturbance, with convective cells bringing light snow, moderate gusty winds, and a further drop in temp's.
Snowpack Summary
Up to 50cm of storm snow has fallen in the last 2 days, with higher amounts observed west of the Divide and up Hwy 93N. Storm slabs have formed on the surface and are bonded poorly to the older surfaces. Below tree-line, the rain has saturated the surface layers and created very unstable conditions.
Avalanche Summary
Lots of natural activity observed today, especially below tree-line in Yoho. Numerous deep, wet slabs to size 3 were seen failing and running to the valley floor. A party of 3 skiers in the Lake Louise backcountry remotely triggered a size 2 slab avalanche from 100m away, 50-60cm deep, 40m wide, and running 200m.
Confidence
Due to the number of field observations
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
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 Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.