Purcells

Pay attention to wind affected snow in open terrain where triggering avalanches is most likely.

THURSDAY NIGHT: Light flurries with 5-10 cm of snow, moderate wind from the southwest, alpine temperatures drop to -15 C.

FRIDAY: Light flurries with some sunny breaks, moderate wind from the west, alpine high temperatures around -10 C.

SATURDAY: Cloudy with light flurries and up to 5 cm of snow, moderate wind from the southwest, alpine high temperatures around -10 C.

SUNDAY: Cloudy with light flurries, moderate wind from the southwest, alpine high temperatures around -6 C.

Thursday's storm resulted in reactive wind slabs on north and east lee features. Large (size 2-3) deep persistent slab avalanches were triggered naturally and with explosives in steep alpine terrain on Monday and Tuesday. It has been over one week since any persistent slab avalanches on the December surface hoar layer have been reported, although there could still be lingering concerns about triggering that layer on isolated slopes in steep treeline clearings.

Surface conditions are variable due to cold temperatures and shifting wind directions over the past few days, but the most recent fresh wind slabs can be found on north and east lee features. A layer of surface hoar that formed in late December appears to be less reactive than it was a week ago and 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.

• Avoid freshly wind loaded terrain features.
• Use caution on large alpine slopes, especially around thin areas that may propagate to deeper instabilities.