Regions
Kootenay Boundary.
Although there has been has been a significant crust forming at most elevations it is recommended to employ a cautious approach at upper elevations where the latest storm only produced snow.
Confidence
Moderate - Freezing levels are uncertain on Wednesday
Weather Forecast
MONDAY: Mix of sun and cloud / Light east wind / Alpine temperature -3 / Freezing level 1400mTUESDAY: Cloudy with scattered flurries / Light east wind / Alpine temperature -1 / Freezing level 1500mWEDNESDAY: Flurries, accumulation 5cm / Light to moderate southwest wind / Alpine temperature 1 / Freezing level 1900m
Avalanche Summary
Reports from Saturday include numerous natural and skier triggered loose wet avalanches at lower elevations (size 1.5) . Reports from Friday include several large natural avalanches including a size 3 persistent slab in the Rossland range and up to size 3.5 deep persistent slabs in the Valhallas (failing on basal facets over 2 m deep).The upper snowpack should stabilize with cooler temperatures when crust form or reform, but deeper persistent weak layers remain under heavy stress and have the potential for large and surprising avalanches.
Snowpack Summary
Rain has soaked the upper snowpack for a second time in a week. This time all the way to mountain tops. Cooling temperatures will have formed a rain crust on the surface, but expect a thick layer of moist snow in the upper snowpack for some time. This heavy snow will stress a number of deeper weak layers including the late-February facet / surface hoar interface (70-120 cm deep), the mid-February crust (90-130 cm deep), and basal facets in shallow snowpack areas.
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
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.