Snow, rain and wind combined with buried weak layers is the perfect recipe for rising avalanche danger. The upper snowpack is complex, keep it simple and use a very conservative approach to terrain selection.
Weather Forecast
A series of pacific frontal systems will bring waves of precipitation to the Interior Ranges. Friday will see overcast skies, precipitation amounts 5-15 mm, ridgetop winds moderate from the SW and freezing levels 1800-2000 m. Continued precipitation on Saturday with amounts up to 15 mm , ridgetop winds light-moderate from the SW and freezing levels near 1900 m. Later Saturday the front will move east setting up for a clearer, drying trend Sunday. Freezing levels will initially drop to valley bottom overnight Saturday then rise steadily during the day with treeline temperatures near 0 degrees. The way this system is tracking, southern parts of this region will likely see less precip amounts then what's posted above.
Avalanche Summary
On Wednesday, several natural slab avalanches and skier triggered avalanches up to size 2 were reported. Most of these avalanches failed on north- easterly aspects above 2000 m. With forecast snow, rain and wind, widespread natural avalanche activity is expected through the weekend.
Snowpack Summary
At higher elevations, up to 20-50 cm of snow sits over a plethora of old surfaces including wind affected surfaces, and/or old wind slabs and crusts which were buried mid-March. Previous strong winds have redistributed new snow into wind slabs on leeward terrain features and lower elevations (below 2000 m) are sporting spring-like, melt-freeze conditions. Digging deeper (40-70 cm below the surface) sits the mid-February facet/ crust interface. This interface has not been as reactive in the South unlike regions to the North. However, it is alive and well in test profiles. It may just require additional load and/ or a change in slab properties before it reaches threshold and becomes reactive. The late-Jan crust/surface hoar layer (around 1m deep) and the mid-January surface hoar (around 1.5m deep) have been dormant for several weeks.
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.