Kootenay Boundary

A Special Public Avalanche Warning Applies for this Region.Natural and human triggered avalanches are very likely on Thursday. Travel in avalanche terrain is not recommended.

Moderate - Freezing levels are uncertain on Thursday

Wednesday night: 10-20 cm new snow / Moderate, southwesterly winds/ Freezing level beginning to rise.Thursday: 20-30 cm new snow / Strong, southwesterly winds / Freezing level rising to 1000-1500 m.(Cooler in the north)Friday: 5-10 cm new snow / Strong, southwesterly winds / Freezing level dropping to around 1000 m.Saturday: Mix of sun and cloud / Moderate, southwesterly winds/ Freezing level hovering around 1000 m.

On Tuesday, there were numerous explosive triggered storm slab avalanches that ran to valley bottoms up to size 3.5 near Kootenay Pass. Additionally, south of Nelson there was a skier triggered size 2 storm slab avalanche on a southeast aspect around 2000m. Heavy snow, strong winds, and warming is elevating the avalanche danger to HIGH on Thursday.

45-85cm of recent storm snow has created touchy storm slabs at all elevations and aspects. Snowfall amounts have been highest around Kootenay Pass and taper dramatically as you go north. These slabs have been reported as being very reactive to human triggers and are sitting on a variety of surfaces; including scoured surfaces in wind exposed terrain, surface hoar(size 2-3 mm) in sheltered locations, and sun crust on steep solar aspects. 50-100 cm of snow now overlies the weak layer of surface hoar(feathery crystals) and facets(sugar snow) that was buried in mid-January. There has only been one recent report of an avalanche on this interface, but this may change with the increasing load. Areas with a shallower snowpack (less than 150 cm) have a generally weak snowpack structure with sugary facets near the ground. This includes shallow alpine slopes and most of the Rossland range. It is possible for storm slab avalanches to step-down to these deeper weak layers, resulting in large, destructive avalanches.