Wind slabs may be found in lee terrain in the alpine and exposed treeline and will be most reactive where they overlie a crust.
Wind slabs may exist in lee terrain features in the alpine and treeline, formed by recent snowfall and westerly winds. These wind slabs will be most reactive where they overlie a slick crust.
Saturday night: Mix of clouds and clear periods, trace of new snow, moderate southwest wind, alpine low -6 °C, freezing level at 700 m.
Sunday: Cloudy, up to 5 cm snow, moderate southwest wind, alpine high -4 °C, freezing level 1500 m.
Monday: Cloudy, 20-30 cm snow, moderate to strong southwest wind, alpine high -4 °C, freezing level at 1500 m.
Tuesday: Cloudy, 10-15 cm snow, moderate to strong westerly wind, alpine high -5 °C, freezing level at 1500 m.
On Friday, small natural dry loose avalanches were observed. A skier triggered cornice resulted in a size 2 avalanche. Skiers triggered a few small wind slab, storm slab and wet loose avalanches.
On Thursday, numerous small size 1 wind slabs, dry loose, and wet loose avalanche activity were observed.
On Wednesday, the region saw a natural cycle of wet loose, dry loose, wind slabs up to size 2, and wet slabs up to size 3.
20-40 cm of new snow overlies up to 20 cm of denser snow above 2000 m and tapers rapidly at lower elevations. 50-60 cm of snow sits over the mid-March interface at upper elevations.
A melt-freeze crust exists on all aspects as high as 2000 m and to mountain top on solar aspects. Below the crust, the top 10-30 cm of the snowpack is moist.
Westerly winds have formed reactive wind slabs on leeward terrain in the alpine and exposed treeline terrain.
The early-December rain crust is approximately a metre off the ground. Reports have recently indicated that large slab avalanches have failed on this interface earlier this week following a rain and warming event. This layer may be dormant now due to colder weather, however, it may appear again during the next big warm-up or with increased load from wind, snow and/or rain.
