Purcells

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Fair - Timing or intensity of solar radiation is uncertain

Monday, Tuesday and Wednesday are expected to be dry and cool, with sunny periods. Winds are generally light from the NW. The freezing level is at valley floor by night and rising to around 1200 m by day. The next storm system may arrive late on Wednesday, but weather models are not in agreement about this.

Several size 1.5-3 avalanches were triggered naturally and with explosives over the last few days in response to storm loading, wind and warm temperatures. A number of cornice collapses and an ice fall have also been reported. Last Wednesday, a skier took a ride in a size 2 persistent slab which failed on the mid-Jan layer in the Dogtooth range. Now that temperatures have cooled, avalanche activity is likely to ease, although direct sun may spark a new avalanche cycle on steep slopes or cause cornices to fail.

Now that the weather has finally cooled after ten days of very warm temperatures and bursts of rain, surface crusts have formed to at least 2000 m. Underneath newly formed crusts, you may find moist snow for a few days yet. At alpine elevations, new wind slabs or storm slabs may be found. Cornices are large and weak. The late-Jan crust/surface hoar layer is 1-2 m deep in the west, and can be found within the upper metre of the snowpack further east. It is variably reactive and still the main concern in many areas. The mid-January surface hoar, deeper again, remains problematic in some areas. The mid-December weak layer may still be on the radar in isolated areas in the east. The mid-November weak layer of crusts and facets can still be found near the bottom of the snowpack. It seems to have been reawakened with warming and has been triggered by explosives during the recent warm spell, taking the entire snowpack with it.