Regions
Kootenay Boundary.
The hazard may change if more rain and higher freezing levels occur in the forecast area.
Confidence
Fair - Freezing levels are uncertain
Weather Forecast
Synopsis: An intense frontal system with subtropical moisture is forecast to arrive on the BC coast in the next 24 hrs. Warm air preceding the Pacific frontal system has already pushed freezing levels up to 2000 metres in some parts of the forecast area.Tonight: Cloudy with flurries and possible 10 to 20cm of precipitation. Strong SW winds and freezing levels climbing to 1700m.Sunday: Cloudy, snow flurries mixed with rain at lower elevations, 5 to 10 cm of snow, winds gusting to strong at ridge tops, freezing levels may climb to 2100m.Monday: Mix of sun and clouds, No precipitation in the forecast, light to moderate winds at ridge tops, freezing level drops to around 1500m. Tuesday: Sunny with cloudy periods, no precipitation in the forecast, light winds at ridge top, freezing level down to around 14500m.
Avalanche Summary
As a result of the rain, warm temperatures and additional snow loading from the most recent storm, numerous avalanches up to size 3 have been reported in the past 24 hrs. In some cases failing through the seasons snow pack to ground. There are also numerous reports of skier accidental and skier remote avalanches up to size 2. Many of these failed on the Feb.10 surface hoar / crust/ facet layers. There is ample opportunity now for a rider or skier to trigger an avalanche that might step down to any of the persistent weak layers that now exist in this years snow pack and produce a very large and destructive avalanche..
Snowpack Summary
The recent storm snows are rapidly settling into a slab that now sits above a variety of old surfaces. There are buried facets on north aspects and sun crust on many south facing slopes. Rains up to 1800m have saturated the upper snowpack. At elevations above the freezing level strong SW winds have have formed winds labs in lee features. There are 3 persistent weak layers now buried in the snowpack, A January 28th layer of surface hoar, facets and crusts, a Feb.10th layer of surface hoar, facets and crusts, and the March 2nd layer of surface hoar, facets and crusts. All of these layers have been noted in recent avalanche activity.
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.
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.