Persistent weak layers are scary and will be more concerning in warm weather.
Rider-triggered avalanches are likely and could be very destructive.
Be mindful of overhead hazards.
Wind slabs remain sensitive to rider triggers. Small wind slab releases may step down to weak layers in the upper snowpack to produce larger, more destructive avalanches.
Mild temperature and wind have been working to consolidate reactive slabs over the mid-February weak layer and the late January crust below it. Wind-loaded areas at higher elevations are the most likely places to trigger this problem.
Periods of sunshine, where they emerge, will destabilize the surface snow on sun-exposed slopes. Loose avalanches may run naturally or with a human trigger.
Strong solar input from Wednesday triggered large persistent slab avalanches (up to size 3) with impressive propagation on alpine slopes. Natural widespread avalanches have been observed continually since Sunday.
Scary large avalanches (size 2.5) were remotely triggered by riders on northerly alpine and treeline slopes. They were triggered 100 to 400 m away and failed on a preserved surface hoar layer, down 60 to 90 cm.
Up to 50 to 60 cm of settling snow covers weak surfaces, including surface hoar or facets in sheltered, shaded areas, and sun crusts on sun-affected slopes. This layer has caused several large remote triggers continually since Sunday. Professionals are concerned about this layer as numerous avalanches are observed on it.
A thin sun crust is visible up to 2000 m on southerly slopes, while extensive strong southerly winds have redistributed recent snow, and scoured exposed areas at treeline and alpine.
A hard crust from late January lies 40 to 80 cm deep beneath weak facets and isolated surface hoar, with recent avalanches failing on it, especially near Whistler.
The snowpack below is strong.
Thursday Night
Cloudy with isolated flurries. 15 to 20 km/h southwest ridgetop wind. Treeline temperature -2°C. Freezing level around 1500 m.
Friday
Mix of sun and clouds. 10 to 20 km/h southwest ridgetop wind. Treeline temperature +4°C. Freezing level around 2500 m.
Saturday
Mix of sun and clouds. 20 to 30 km/h southwest ridgetop wind. Treeline temperature +4°C. Freezing level reaching 2500 m.
Sunday
Mostly cloudy. 10 to 20 km/h northeast ridgetop wind. Treeline temperature -2°C. Freezing level around 1500 m.
More details can be found in the Mountain Weather Forecast.
