Recent fresh snow has been redistributed into pockets of wind slab at tree line and in the alpine. Use caution in wind exposed terrain.
Fresh wind slabs may form during the day on Thursday and could become more reactive throughout the day with ongoing strong winds and a bit of fresh snow.
Triggering large, deep persistent slab avalanches is a low likelihood but high consequence problem that is most likely in shallow, rocky start zones.
WEDNESDAY NIGHT - Mainly cloudy with isolated flurries / southwest wind, 20-30 km/h / alpine low temperature near -8
THURSDAY - Cloudy with scattered flurries, up to 5 cm / southwest wind, 30-50 km/h / alpine high temperature near -3 / freezing level 1300 m
FRIDAY - Cloudy with scattered flurries, up to 5 cm / southwest wind, 20-30 km/h / alpine high temperature near -2 / freezing level 1500 m
SATURDAY - Mainly cloudy with scattered flurries / southwest wind, 20-30 km/h / alpine high temperature near -5 / freezing level 1400 m
With strong winds and some fresh snow in the forecast, there could be new wind slabs forming on Thursday and they may become increasingly reactive throughout the day.
Over the past three days there have been a few reports of natural and explosives triggered avalanches up to size 3. A few of these were deep persistent slab avalanches that failed near the base of the snowpack.
There have been no reports of human triggered avalanches over the last three days.
Around 15-20 cm of recent snow over the past week and strong southwest wind has produced wind slabs in lee terrain features. Strong southwest winds on Thursday may form fresh and potentially reactive wind slabs at upper elevations.
A layer of surface hoar that formed in late December appears to be gaining strength. It can be found 70 cm deep around Golden, 30 cm deep around Invermere, 70 cm deep around Kimberley, and 100 cm deep along Kootenay Lake.
As usual for the Purcells, the base of the snowpack contains basal facets and it remains possible to trigger these deep weak layers in shallow rocky start zones or from a heavy trigger such as a cornice fall or explosives.
