Cool protected north facing slopes in the June Mountain area have weak faceted snow at the bottom and above and below sun crusts in alpine terrain. Fractures propagated in two out of three extended column tests on 27 and 29 taps. The overlaying slab was the February 28-March 2 storm snow. While it took many taps to get the column to fracture and propagate, the fact that propagation occurred is more important than the number of taps- those persistent weak layers need a lot of force to activate but they are weak and will remain an avalanche problem probably until the snow melts. I noted a thick layer of depth hoar at the base of a 3-4 ft deep snowpack but this layer did not react.
Similar results were reported on an east slope in the Red Cone area in the Mammoth Basin. Observers reported an ECTP 30 on 1 mm facets above a crust about 29 inches down and believed this crust represented the old snow surface prior to the March 7-9 storm. A week ago, extended column tests show propagation on the old snow/Feb. 28-March 2 storm snow. This winter’s buried weak layers are different than last year’s because buried weak layers continue to react in tests in March. At the same time last year, wet snow avalanches were widespread.
Depth hoar, June Mtn area ECT, failed on small facets, east slope near Red Cone Mammoth Basin