Kootenay Boundary

Continued snow and wind Sunday night will keep danger ratings elevated at upper elevations. Stay conservative with terrain choices as the upper snowpack adjusts to this most recent load.

Moderate

The Kootenay Boundary should see one more shot of snow and wind Sunday night. Monday marks the beginning of a shift towards a more classical spring pattern that follows a strong diurnal temperature swing with very little in the way of precipitation expected for the foreseeable future. SUNDAY NIGHT: Freezing level holding at 1500 m, 5 to 15 cm of snow, strong southwest winds. MONDAY: Freezing level starting near valley bottom rising to 1400 m, 1 to 3 cm of snow, moderate southwest winds. TUESDAY: Freezing level starting near valley bottom, rising to 1500 m, no significant precipitation expected, moderate west / northwest winds. WEDNESDAY: Freezing level starting near valley bottom, rising to 1500 m, no significant precipitation, light variable winds.

On Saturday numerous human triggered storm slab avalanches to size 2 were reported on northwest, north, northeast and east facing aspects between 1800 and 2200 m. One deeper persistent slab avalanche was triggered after a snow-cat intentionally pushed a cornice onto a north facing feature at 2200 m resulting in a size 3 avalanche that was 100 cm deep on average. Check out the Mountain Information Network for more details about a human triggered size 2 avalanche on a NW facing slope along the Bonnington Traverse. On Thursday reports included numerous natural avalanches up to Size 3 in response to heavy loading from snow, wind and rain. Most of the natural avalanches were storm and wind slabs, but a few persistent slabs also ran naturally on the late February persistent weak layer. Explosives and other artificial triggers (i.e. snow cats) produced additional Size 2 to 3 persistent slab activity, with remote and sympathetic triggers as well as a 50 to 100 cm thick slab releasing from the impact of the dropped charge, before it exploded.

20 to 40 cm of fresh snow has fallen in the last 48 hours combined with moderate southwest winds which have likely created deep wind slabs on the leeward side of ridgecrests and mid-slope terrain features. In some drainages these fresh storm and wind slabs may be sitting on a thin crust that was initially buried on March 11th. A second curst, (the early March melt/freeze crust) can be found down 30 to 80 cm. A persistent weak layer buried late-February is typically down 60 to 120 cm and remains sensitive to triggering as indicated by recent avalanche activity. This weakness is widespread buried surface hoar on sheltered slopes above 1700 m, and a crust potentially with associated facets on previously sun-exposed slopes (primarily south aspects).