Regions
Banff Yoho Kootenay.
During the heat of the day, loose wet avalanches are almost certain in steep and confined terrain on solar aspects. Ice climbers should avoid avalanche terrain until things cool down.
Weather Forecast
Expect the daily diurnal temperature variation to continue, each day a little bit warmer than the last. Sunday temps could climb to 4 degrees. Clear skies will also provide a condition for intense solar radiation. Wind will remain light from the SW.
Snowpack Summary
Last weeks storm of 10-25 cm sits on a supportive midpack. The surface snow has had some wind transport in the alpine forming thin wind slabs .A sun crust has formed on solar aspects at treeline and below. The deeper facet layers down 80-150 cm remain weak and are currently dormant, but could become active with the warm days ahead.
Avalanche Summary
Although outside the forecast region, a group of ice climbers were hit by a loose wet avalanche that caused moderate injuries on the ice climb 'Kitty Hawk'. Evidence of a loose wet avalanche cycle was isolated to steep solar gullies. Also observed were a few size 2 slabs on steep solar convex rolls.
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 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.