Regions
Kootenay Boundary.
Loading and warm temperatures will have a destabilizing effect on the snowpack. Watch your overhead hazard as weak layers may "wake-up" with the potential for large and destructive avalanches.
Confidence
Poor - Due to the number of field observations
Weather Forecast
The sub-tropical storm cycle will continue through Thursday bringing another round of moderate to locally heavy precipitation, strong southwest winds and freezing levels at about 2300m. As the system moves east on Friday there may be lingering light snowfall, light southwest winds and freezing levels at about 1500m. By Saturday a dry ridge should develop bringing clearing skies, light northwest winds and freezing levels at about 800m.
Avalanche Summary
Numerous size 1 loose wet avalanches were observed in the Kootenay Pass area on Tuesday. Although observations have been limited, I suspect this activity has been fairly widespread with the wet weather. Rain or loading from snow may also spark destructive avalanche activity on persistent weaknesses which exist near the base of the snowpack. If you have any avalanche observations, please share them on our new Mountain Information Network. For more details, go to: https://avalanche.ca/blogs/VIYBuScAAJdbdqPz/m-i-n-intro
Snowpack Summary
Rain has likely saturated and weakened the upper snowpack in most areas. The extent of saturation will depend on elevation and the amount of rain that fell. At upper elevations, precipitation may have fallen as moist snow, and may be adding load and cohesion to a storm slab which overlies a weak layer of facets, surface hoar, a hard rain crust or a combination thereof.Near the base of the snowpack is a crust/facet combination which is a concern at higher elevations in many parts of the region. This destructive layer continues to produce whumpfing, and may see a "wake-up" with warming and the load from rain or snow.
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.
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.