Human triggered avalanches continue to fail on a buried weakness 40-60 cm down. Avalanche danger may be higher if you see more then 20 cm of new snow. Keep it simple, use a conservative approach to terrain.
Confidence
Fair - Intensity of incoming weather systems is uncertain
Weather Forecast
A well-organized pacific frontal system will likely arrive onshore tonight. Interior regions will start to see effects of this system by Thursday with cloudy skies and light precipitation 5-10 mm. Ridgetop winds will blow strong from the West and freezing levels will hover between 1600-1800 m. Friday and Saturday will bring continued precipitation with accumulations up to 20 mm. Ridgetop winds will be moderate from the SW and freezing levels 1800-2000 m. On Sunday a ridge builds over the Interior keeping things dry and clear, yet again....
Avalanche Summary
On Tuesday, reports from the region indicated numerous natural slab avalanches up to size 2.5, and a skier remote (15 m away) slab avalanche size 2, failing on the mid-February facet/ crust interface which remains alive and well.
Snowpack Summary
At higher elevations, new snow up to 60 cm sits over a plethora of surfaces including moist snow, crusts, wind affected surfaces, and/or old wind slabs which may still be reactive to rider triggers. Previous strong winds have redistributed new snow into wind slabs on leeward terrain features. Lower elevations up to treeline are sporting spring-like, melt-freeze conditions. The recent storm snow is sitting over a weak facet/crust layer that was buried in mid-February and has been quite reactive recently. The late-January crust/surface hoar layer (over 1m deep) and the mid-January surface hoar (around 1.5m deep) have been dormant for several weeks.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.