Be alert to a developing wind slab problem.
Confidence
Fair - Due to the number of field observations
Weather Forecast
Expect light snow on Sunday, then it becomes cold and clear with light to moderate N-NE outflow winds.
Avalanche Summary
On Friday a few size 1-1.5 wind slabs failed in steep terrain. On Wednesday, a snowboarder triggered a size 2-2.5 slab on a north aspect at 1900 m in the Callahan area. The crown was 10cm-100cm deep. The slab is believed to have failed on a crust. The snowboarder was buried, but was recovered safely by companion rescue.
Snowpack Summary
10-20cm new snow overlies large surface hoar crystals which sit above old wind slabs and other variable surfaces. A deeper layer of surface hoar buried in mid-December (now down 40-70cm) has been gradually gaining strength, but may still be a concern in some areas. The mid and lower snowpack contain several old crust layers, one of which may have been the failure layer for a recent burial (see avalanche summary).
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.