Regions
Kootenay Boundary.
The next big change is on Sunday: Sunny, warm weather will be driving avalanche problems.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain on Sunday
Weather Forecast
The clouds will clear out Saturday afternoon, giving way to pleasant weather on Easter Sunday. Back to moist spring weather on Monday afternoon/eveningSUNDAY: Clearing with some good sunshine. Freezing level rising to 2100 m in the afternoon. Winds light southerly. MONDAY: Snow late in the day (5-10cm) above 1900m. Winds 10-25 km/h from the south. TUESDAY: Snow, heavy at times (10-25cm possible by late Tuesday). Freezing level around 2000 m. Winds light-moderate westerly.
Avalanche Summary
On Thursday, we had reports of touchy conditions in the Rossland Range with upwards of 35cm of new snow falling at treeline and above, running easily on a temperature crust. Several loose wet avalanches to Size 2 were reported near Kootenay Pass, running on all aspects between 1800m and 2100m elevation.
Snowpack Summary
This region experienced a wide variation in snowfall amounts on Thursday - most areas saw 5-10 cm of wet heavy snow above 1600m; however, the Rossland Range was the 'bulls eye' for enhanced convective snowfall and received upwards of 35cm! An additional 5-10cm of snow fell above 1500m on Friday. The snow and shifting wind directions created fresh wind slabs on a variety of aspects at Treeline and above. The new snow will be prone to sliding in steep terrain where it is sitting on a crust. Cornices are large in some areas and could trigger large avalanches when they fail.
Problems
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.
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.