Persistent Weak Layer

Decreasing Danger

No thick or cohesive hard wind slabs were detected on our tour on Saturday. We dropped a fairly large and hard cornice on a steep (~40 degree) N facing avalanche gully which failed to trigger a slide, despite visible wind loading. A soft slab (slough) resulted from this test, as well as a smaller cornice-drop test on a nearby steeper (~45 degree) NW avalanche gully, however, neither soft slab entrained much or ran far, probably because of the really low density fresh snow. The top 100-200' of a W facing slope of roughly 30 degrees was wind-scoured and did not have any evidence of a wind slab. A very open E facing bowl f approximately 30 degrees which was being actively wind-loaded on Saturday also showed no evidence of wind-slab. We kicked around exposed ridges containing a few excellent test slopes on several aspects, which also failed to yield any red-flags with the exemption of some new-snow surface cracking.

Cornice

Increasing Danger

Some stiffer, larger, cornices are finally materializing this winter. We saw two crowns just below an E/SE ridge which were probably avalanches triggered by cornice collapse above. This cornice was several feet thick, and, if similar to others we were previously testing, was probably hard and thick for 3-5' and then topped by a 1-2' thick soft but cohesive layer. The depth or extent of these slides was not investigated, however, we later skied across the run-out gullies about 2000' below where both occurred and could not see any evidence of avalanche activity in either gully above so perhaps they were short running slides, or maybe the avalanche evidence was covered over by recent snowfall - hard to say. If temperatures warm up this week then more frequent cornice collapsing could occur.