Kootenay Boundary

Light snowfall and strong winds will continue to build wind slabs on Thursday. Loose dry avalanches remain a concern in steep terrain.

Moderate - Intensity of incoming weather systems is uncertain

5-10 cm of new snowfall is expected on Thursday with alpine winds becoming strong from the southwest and freezing levels reaching around 700 m. Another 5-10 cm of snowfall is expected Thursday overnight with strong alpine wind from the southwest. Lingering flurries are possible Friday morning and sunny conditions are expected Friday afternoon. Alpine wind should become light from the northwest and treeline temperatures are forecast to be around -10C. A mix of sun and cloud is currently forecast for Saturday with a weak storm system arriving Saturday night.

On Tuesday, numerous natural slab avalanches up to size 2 were reported at treeline in the Whitewater area. Several natural loose dry avalanches up to size 1.5 were also observed on steep southerly aspects at 1700-2100 m elevation in the Kootenay Pass area. A skier triggered avalanche also occurred in the Rossland area on Tuesday which was reported to have occurred on the mid-December interface down 40-60 cm.  This is the first avalanche on the interface in the past week or so.  It is uncertain if this is an isolated problem or an indication that the layer is waking up.  We will continue to closely monitor this interface.On Thursday, wind slabs are expected to be the main concern. Light new snowfall and strong southwest winds will continue to load leeward features.  Ongoing wind slab formation has been reported on Tuesday and Wednesday.  Loose dry avalanches remain a concern in steep terrain, especially in areas sheltered from the wind.

30-50 cm of low density snow has accumulated since Monday. The new snow sits over wind scoured surfaces or old wind slabs in exposed terrain and surface hoar up to 5 mm in sheltered areas. In exposed terrain, strong southerly winds have redistributed the new snow and wind slabs exist in leeward terrain features. A freezing rain crust from last week is now down around 60 cm and reports suggest it is generally not creating an instability in the snowpack. The mid-December interface is now down 70-100 cm. While the layer has recently been considered dormant in region, a skier triggered avalanche on Tuesday was reported to have occurred on this interface in the Rossland area. It will be important to continue to watch how this layer reacts in coming days.