Avalanche: Slate Canyon

We skinned up Slate Canyon on the afternoon of March 11. We were wary of this particular avalanche path given the recent rain, warming, and likely windloading off the top of Buckley. The debris deposit both from the most recent and previous avalanches was impressive. The debris pile was about 300 feet in length and looked to be 20+ feet deep in spots (hard to capture with pictures). It has completely wiped out the trail. The most recent debris ran full track down into the stream bed and some oven-size chunks of snow were visible. There was about an inch of snow over the debris, indicating that it avalanched the night of March 10 or early in the morning March 11, sometime before the snow subsided.

Further up-canyon, we dug a hasty pit at 7100' on an east-northeast facing slope. We found 1.5 meters of total snowpack. The top 20 or so inches of snow formed a thick, heavy cohesive slab and sat on loose, wet grains (maybe old facets that got soaked with the rain?). These grains were so loose that some would spill out as soon as we exposed them in the pit, and the cohesive slab on top was obvious while digging and with finger tests. Seems possible that the large debris pile we saw was the result of an avalanche that failed on this layer. Hard to say for sure. Upon seeing how cohesive the top slab of snow was and what it sat on, we proceeded carefully down the ridge we ascended.