Regions
Northwest Coastal.
Storm slabs will likely be reactive to skier and rider triggers. Ridgetop wind will switch from the East to the West potentially forming wind slabs on most aspects. Stick to simple terrain first while gathering observations.
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
Overnight Thursday: New snow 5-10 cm accompanied by strong easterly winds and freezing level at valley bottom.Friday: Cloudy with possible sunny periods. Ridgetop winds light gusting strong from the northwest. Alpine temperatures near -4 and freezing levels 800 m.Saturday: Mostly cloudy. Snow amounts near 5-10 cm and ridgetop wind strong from the southwest. Alpine temperatures near -4 and freezing levels 500 m.Sunday: Cloudy with snow amounts 5-10 cm. Freezing levels near 1000 m. Ridgetop winds mostly light with strong gusts from the southwest.
Avalanche Summary
On Thursday, a few natural wind slab avalanches were reported up to size 2.5 from steep alpine features on northerly aspects. Wednesday was a similar story showing a natural cycle of wind slab avalanches up to size 2.5 occurred in the alpine.
Snowpack Summary
Up to 10 cm of new snow overlies a variety of buried snow surfaces including pockets of wind slab, a melt-freeze crust on sunny aspects and wet snow down low. On March 9th, surface hoar and/or facets (on sheltered, shady aspects) were buried by the last significant snowfall down 10-25 cm. The new snow will likely have a poor bond to the old snow surfaces.Deeper in the mid-pack, layers of crusts, facets, and isolated surface hoar buried 50 to 100 cm exist from mid- and late-February and a surface hoar/ crust layer from January is buried around 150 to 200 cm. Near the bottom of the snowpack, sugary facets exist in colder and dryer parts of the region, such as the far north.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.