Regions
Kootenay Boundary.
Forecast warm weather and potential sunny periods Friday will keep the avalanche danger elevated at upper elevations
Confidence
Moderate - Timing or intensity of solar radiation is uncertain on Friday
Weather Forecast
FRIDAY: Mix of sun and cloud / Light southwest wind / Alpine temperature -1 / Freezing level 1800mSATURDAY: Cloudy with sunny breaks and isolated flurries / Moderate southwest wind / Alpine temperature -2 / Freezing level 1700mSUNDAY: Mix of sun and cloud / Light to moderate northwest wind / Alpine temperature -5 / Freezing level 1400m
Avalanche Summary
On Wednesday there were reports of both natural and explosives controlled storm slab avalanches 20-40cm deep to size 2 on southerly and northwest aspects at tree line. One report detailed a size 2 remotely triggered avalanche running on the melt freeze crust formed by the March 21 warming event. This ran on an east aspect at 1900m and was 50cm deep. There were also reports of skier controlled avalanches at tree line to size 1.5 on east an north aspects.
Snowpack Summary
A series of snowfalls throughout the past week accumulated roughly 60-90 cm of new snow in the region. Periodic high freezing levels and solar exposure over the same period formed a variety crusts within the storm snow at both lower elevations and on solar aspects. This all overlies a rain crust that formed mid-March at all elevations. At upper elevations, above 2100m approximately, the late and mid-February persistent weak layers (100-150cm down) and basal facets in shallow snowpack areas may still exist.
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.
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.