Regions
Kootenay Boundary.
Spring conditions. Watch for rain weakening the snowpack.
Weather Forecast
A cold front arriving overnight and lingering on Sunday brings 10-15 mm precipitation, with moderate to strong SW winds. The freezing level should fall to around 1800 m by Sunday afternoon. A mix of sun and cloud, light winds and mild temperatures are expected on Monday and Tuesday.
Avalanche Summary
Most operators have shut down for the season. Please continue to share your backcountry observations through the Mountain Information Network.
Snowpack Summary
As temperatures gradually cool through the weekend, loose wet and wet slab avalanches will become less likely. Storm slabs may develop in the alpine as the cold front passes through. At lower elevations, monitor the overnight freeze of the snow surface. If the snow surface does not freeze overnight or if the crust is thin or breakable, daytime heating or rain will weaken the snowpack much more quickly than if there is a well frozen thick crust. Low elevation and thin snowpack areas are isothermal.
Problems
Wet Slabs
Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.
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.
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.