Purcells

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

FRIDAY NIGHT: Increasing clouds, light to moderate southwest wind, alpine temperature -15 C, freezing level below valley bottom.

SATURDAY: Cloudy with light snowfall, accumulation 2 to 5 cm, moderate to strong southwest wind, alpine temperature -12 C, freezing level below valley bottom.

SUNDAY: Mix of sun and cloud with isolated flurries, accumulation 1 to 3 cm, moderate southwest wind, alpine temperature -7 C, freezing level 500 m.

MONDAY: Mix of sun and cloud with isolated flurries, accumulationg 1 to 3 cm, moderate southwest wind, alpine temperature -3 C, freezing level 1000 m.

On Thursday and Friday, wind slab avalanches were triggered naturally, by skiers, and explosives. They occurred on north and east lee terrain features, generally at and above treeline. They were 10 to 30 cm deep.

The last deep persistent slabs were reported on Monday and Tuesday. They were large (size 2-3) and were triggered naturally and with explosives in steep alpine terrain. 

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.