Watch for pockets of wind slab at upper elevations. Don't forget about a buried weak layer that remains triggerable.
New wind slabs have started to form as new snow accumulates with southwest wind. They may be small but reactive if they bond poorly to the old surface.
Portions of the north of the region (e.g. Duffey, Hurley) have a a weak layer of faceted grains above a hard melt-freeze crust that is found 30 to 60 cm below the snow surface. A few avalanches over the past week have released on it, with more activity observed in the neighbouring Sea to Sky region. It has been most problematic on north to northeast aspects around 1900 m to 2100 m.
Saturday night: Cloudy with snowfall, accumulation 2 to 5 cm, 20-30 km/h south wind, alpine temperature -5 C. Freezing level 900 m.
Sunday: Cloudy with snowfall, accumulation 2 to 5 cm, 20 km/h southwest wind, alpine temperature -3 C. Freezing level 1600 m.
Monday: Cloudy with snowfall, accumulation 5 to 15 cm, 40-60 km/h southwest wind, alpine temperature -3 C. Freezing level 1600 m.
Tuesday: Cloudy with snowfall, accumulation 5 to 15 cm, 40-60 km/h southwest wind, alpine temperature -3 C. Freezing level 1500m.
No new avalanches reported on Thursday or Friday.
A rider triggered a persistent slab avalanche along the Duffey on Wednesday, occurring at 2000 m on a northeast aspect. Another suspected persistent slab avalanche was triggered by a rider on Tuesday in the north of the region. Both slabs were around 30 to 40 cm thick, resulting in small avalanches (size 1 to 1.5). It remains possible that humans could trigger this layer, where it exists.
Looking forward, wind slabs may begin to form on Friday and into the weekend, which may not bond well to underlying layers.
Small amounts of new snow and southwest wind have likely formed small wind slabs in lee terrain features. The snow accumulates onto variable surfaces. On sun-exposed slopes and on all aspects at low elevations, the snow will build on a hard melt-freeze crust. Elsewhere, it will fall onto previously wind-affected snow at higher elevations and perhaps a thin layer of surface hoar or faceted snow in sheltered areas.
Around 30 to 60 cm deep, sugary faceted grains may be found around a melt-freeze crust that formed February in the north of the region (e.g., Duffey, Hurley). To date, the layer has been most prevalent on north to northeast aspects around 1900 to 2100 m. This layer should be treated as suspect anywhere it exists. Check out this forecaster blog for more info. Various crusts may be found in the south of the region (e.g., Coquihalla, Manning) but reports suggest they are bonding to the snowpack and are not an avalanche concern.
There are no deeper concerns at this time.
