Expect deeper, more reactive new snow in the lee of ridges and exposed terrain features. Make a plan to step back from bigger terrain as winds increase over the day.
New snow and wind have formed small wind slabs near ridge crests. A forecast uptick in southwest winds could drive an increase in slab formation on Friday.
New snow has been adding to the load over weak layers from early February. Surface avalanches may have potential to step down to this layer to create a larger, more destructive avalanche.
Wednesday's reports showed 5-10 cm in the Whistler area yielding small slab and dry loose results with ski cuts and explosives control. Slabs were more restricted to north aspects.
The previous week had a more sporadic pattern of wind slabs on a range of aspects. These were triggered on buried persistent weak layers of facets and more isolated surface hoar.
There remains uncertainty about the possibility for larger surface avalanches to step down to these weak layers.
10-20 cm of recent snow now overlies a mix of previous surfaces that includes crust on south aspects and on all aspects at lower elevations, faceted snow and/or small surface hoar in sheltered features, and previously wind-affected surfaces in the open. Areas where wind loading has increased the depth of new snow and where larger preserved surface hoar is buried are the most concerning.
30 to 40 cm of snow sits above an older layer of faceted snow or more isolated surface hoar at treeline and above. Just below it, a widespread, thick crust is about 30 to 60 cm deep. This problematic combination remains a concern as it adjusts to the load above it.
The snowpack is well bonded and strong below this crust.
Thursday night
Cloudy with isolated flurries. 5 to 15 km/h southwest alpine wind, increasing. Freezing level around 1400 m.
Friday
Cloudy. 15 to 35 km/h southwest alpine wind, increasing. Treeline temperature -2 °C with freezing level to 1400 m.
Saturday
Cloudy with flurries bringing about 5 cm of new snow, including overnight amounts. 25 to 35 km/h southwest alpine wind. Treeline temperature -4 °C with freezing level to 1200 m.
Sunday
Cloudy with moderate to heavy snowfall bringing 20 - 30 cm of new snow, including overnight amounts. 40-65 km/h southwest alpine winds, increasing. Treeline temperature -4 with freezing level to 1100 m.
More details can be found in the Mountain Weather Forecast.
