Plenty of weak snow failed during the 20 Dec storm: surface hoar, facets below a crust, and density changes mid-storm. Deepest crowns to 35cm
Signs of Unstable Snow
Did you see shooting cracks?
Did you experience collapsing or whumpfing?
Temps were 5F/6F at the car with OVC to CLR sky and high westerly winds shifting to calm, easterly flow. We saw plenty of recent storm slabs that had failed naturally mid-storm and also ski cut several D1.5 slides on rollover features above terrain traps. Crowns to 35cm, with snow breaking down to 12/8 in the deepest slides. Shallower slides were on facets below a crust, likely 12/18. A quick crown profile from a natural D1.5 storm slab found facets below the crust as the deepest layer of failure. Ski cuts triggered small slides that ran 50-60' in large concave features, with relatively well connected storm slabs on sub-ridges.
Observed Avalanche Problem #1:
Big collapse on a 125cm wind slab. 3800' E. Surface hoar below. Cross-loaded feature loaded from recent westerly winds. While worried mostly about storm snow over facets this one caught us by surprise breaking trail.