Sun and daytime warming can quickly change snow conditions. Avoid steep slopes if the snow is moist, and stay well clear of cornices, which may weaken and threaten slopes below.
Isolated pockets of wind slab may linger above 1400 m in direct lee features like the downwind side of ridges, peaks, and terrain breaks.
A persistent weak layer of faceted snow surrounding a firm crust is buried 1–2 m deep. While difficult to trigger, large loads—such as a cornice fall onto the slope below have proved to trigger this layer.
Watch for surface snow becoming moist and back off steep slopes while solar radiation is intense.
On Thursday, the NW Field Team saw a natural size 3 persistent slab in the alpine on a west aspect. They suspect it was up to 24 hrs old.
On Wednesday, reports of steep sun-facing slopes shed small wet loose avalanches up to size 1.
On Tuesday, a large, size two avalanche was triggered by a snowmobile. The release was in an open alpine feature and may have involved a weak layer down 75 to 150 cm.
Sunny skies, daytime warming and continued northwest winds have created variable surface conditions. In the alpine, isolated pockets of wind slab may exist on northerly slopes. Melt-freeze conditions exist on sun-facing slopes.
At treeline and below, moist and/or refrozen surfaces exist on sunny slopes, and some dry snow (up to 10 cm) is likely be found on northerly slopes. Below 700 m, the snowpack is becoming isothermal. On sun-facing slopes, the surface snow is moist.
A thick crust with faceted snow from late January can be found at a wide range of depths, from 75 to 150 cm. A cornice fall (large load) may be enough to trigger this slab.
Thursday Night
Mostly clear skies. 20 km/h west ridgetop wind. Treeline temperature 0 °C. Freezing level 1500 m.
Friday
Mix of sun and clouds. 10 km/h southwest ridgetop wind. Treeline temperature 1 °C. Freezing level 2000 m.
Saturday
Mix of sun and clouds. 1 mm of precipitation as snow or rain at treeline. 10 km/h north ridgetop wind. Treeline temperature 2 °C. Freezing level 1800 m.
Sunday
Mostly sunny. 10 km/h southeast ridgetop wind. Treeline temperature 2 °C. Freezing level 2000 m.
More details can be found in the Mountain Weather Forecast.
