Saturday, April 8, 2017 - 12:30pm
Observed debris at the bottom of Dempsey Don't almost to the bottom of the path (stopped a few 100 feet before the meadows). We also saw evidence of a natural slide in The Hose at about half way down that had taken out some smaller trees. In both cases the slide debris was covered by at least 10-20 cm of new snow, so they likely occured late afternoon/evening yesterday (Friday). Visibility was generally poor and still storming at the ridgeline, so we weren't able to see any crown lines or get a sense of what exactly released.
We started at the Old Mammoth Road trailhead and toured up by Mammoth Rock. We dug a pit at 9500' on a somewhat sheltered 30 degree NNE slope. There was 100 cm of new snow with 20 cm of fist hard light snow from overnight on top, then another layer of 4F snow extending down to 40 cm below the surface. Below that, the new snow increased in density fairly uniformly from 1F to P- at about 100 cm. The old snow was still wet, but I didn't observe any free water in the back.
CT11 Q3 15cm
CT15 Q2 35cm
ECTN 11 15cm
ECTP 21 35cm
Ski Pen: 13cm
Boot Pen: ~95cm
The interface between the new snow and the old snow a meter down appeared fairly well bonded today - at this point I'd say the primary avalanche concern is new wind slabs forming near ridgelines. The density change 40cm down also has propagation potential although it would likely be fairly hard to trigger from a skier.
We skied trees between The Hose and Dempsey's, and another lap to skier's left of The Hose, but we did not observe any signs of instability other than the slide debris.
Gusty winds near the ridgelines.