Avalanche Forecast
Issued: Feb 7th, 2017 3:40PM
The alpine rating is Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Wednesday: Mostly cloudy / Light, southerly winds/ Freezing level valley bottom.Wednesday night: 5-10 cm new snow / Moderate, southwesterly winds / Freezing level valley bottomThursday: 15-20 cm new snow / Strong, southwesterly winds / Freezing level 800m.Friday: Mostly cloudy with flurries / Moderate, southwesterly winds / Freezing level 1000 m.
Avalanche Summary
On Monday, numerous size 2.5 natural and explosive triggered storm slab avalanches were reported at Kootenay Pass. The avalanches were reported as having impressive propagation up to 150 m wide. North of Nelson, there was a widespread natural avalanche cycle to size 2. South of Nelson, there were several size 2.5 natural storm slab avalanches reported.
Snowpack Summary
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.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 8th, 2017 2:00PM