Stick to small slopes with limited consequences and no overhead hazard.
There is uncertainty about the reactivity of persistent slabs, conservative terrain choices are your best defense.
A persistent weak layer consisting of facets over a hard crust still has the potential to produce large, destructive avalanches. Avoid overhead hazard; remote triggering is a concern with this layer.
Storm slabs will likely remain rider triggerable, especially on north and east aspects at treeline and above. Storm slabs could step down to deeper layers, resulting in large avalanches.
Last weekend, numerous large (up to size 3) avalanches were reported, both natural and human triggered, all suspected to have failed on the late January crust/facet layer. They were mostly at treeline, although two human triggered avalanches were in open, alpine or alpine-like terrain.
Looking forward, we expect that humans are likely to trigger avalanches in the recent storm snow, that could become larger and more destructive if they step-down to deeper weak layers.
Storm totals are expected to reach 30 to 50 cm by Friday afternoon, along with continuing strong west winds, making for deeper and more reactive slabs in leeward and cross-loaded terrain.
Rain has saturated the top 10 to 20 cm below treeline.
The new and settling snow overlies a melt-freeze crust on solar aspects and lower elevations, and wind-affected surfaces at higher elevations.
50-100 cm below the snow surface, two persistent weak layers can be found, buried in late January and early February. These weak, sugary facets (over a crust on the late January layer), have the potential to produce large, destructive avalanches.
Thursday Night
Cloudy. 5 to 10 cm of snow. 30-50 km/h west ridgetop wind. Treeline temperature -5 °C. Freezing level 1000 m.
Friday
Cloudy. 4 to 10 cm of snow. 40 km/h west ridgetop wind, increasing to 60 km/h by the end of the day. Treeline temperature -3 °C. Freezing level 1300 m.
Saturday
Mostly cloudy. 10 to 15 mm of precipitation as snow or rain at treeline. 70 km/h west ridgetop wind. Treeline temperature -1 °C. Freezing level 1700 m.
Sunday
Mostly cloudy. 10 to 25 cm of snow. 70 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1500 m.
More details can be found in the Mountain Weather Forecast.
