If you head high into the mountains to search for dry snow, watch for pockets of wind slab that are still possible to trigger. At lower elevations a thick surface crust reduces the likelihood of avalanche activity.
Pockets of wind affected snow from the strong south-southwest winds may still be reactive to a human trigger. Take care around wind loaded ridgelines and cross loaded features mid slope.
Unsettled conditions and shifting freezing levels remain until Monday, when the next front approaches bringing light snow to the Coast.
FRIDAY NIGHT: Cloudy with light snowfall, up to 5 cm. Strong southwest winds. Freezing levels sit below 1500 m.
SATURDAY: Cloudy with a chance of flurries. Freezing levels stay below 1000 m. Strong westerly winds. Alpine high -2.
SUNDAY: Mostly cloudy with a chance of flurries. Strong westerly winds. Freezing levels around 1500 m. Alpine high -1.
MONDAY: Light snowfall begins, with up to 5cm over the day. Freezing levels around 1500 m. Moderate southwest winds. Alpine high -1.
Recent heavy precipitation and warm temperatures produced widespread natural avalanche cycles at all elevations. At treeline and below saw wet loose and slab avalanche cycles to size 3 on all aspects, during the most intense rain and warming. Upper treeline and alpine terrain produced storm slabs to size 3 in most areas.
Several very large avalanches have been noted since the storm, up to size 4 where terrain allows. Of note, an avalanche was naturally triggered near Harrison Lake, in the South Coast region. This was thought to have started as a cornice fall which triggered a large storm slab and stepped down to a deeper layer. It likely failed on the weak early December facets as it was up to 3 m deep in places and ran approximately 1300 m.
Heavy precipitation over the last week has created a variety of surface snow conditions. Strong southwest winds have created pockets of dry snow at alpine elevations on north through east facing slopes. Precipitation fell as wet snow or rain below 2200m, creating saturated snow that is forming a melt freeze crust with moist snow below.
A crust that formed prior to the rain was observed up to 2000m. This is now buried up to 30 cm deep and may be breaking down at lower elevations.
Two buried weak layers of sugary, faceted grains sit in the middle and lower snowpack, at 100cm deep and 150-250 cm deep. The deeper layer was formed by heavy rain followed by a cold spell in early December. It is most prominent between 1700 and 2100 m. Avalanches on this layer are large, but sporadic and isolated. The most likely place to trigger it would be in thin, rocky snowpack areas.
The lower snowpack is well-settled and strong.
