We dug many pits. You only need to dig a foot or two until you hit a stout crust from rain and warm temps in mid December. Maybe the 15th. At elevations below 7500 feet the snow got wet mostly from rain which switched to snow. Then temperatures got very cold and created a steep temperature gradient. 32 degrees F at the wet, rain soaked snow and temperatures approaching 0 degrees F or colder at the snow surface. This weather event (rain, snow and cold temps) was affected all aspects and seems to be more dependent of elevation.
However, this faceted layer produced consistent ECTN's (they would break but not propagate). Additionally it was very stubborn and would not crack or produce any alarming results in any informal tests. I was very surprised given how soft it is.
Most open slopes had small (2mm) surface hoar crystals. The next 2 days of high pressure will have perfect conditions for creating near surface facets as well. If this happens and this weak layer survives and is buried it may make the deeper layers irrelevant.
Images below are snow profiles from two different elevations. The first is from 6800 feet and all aspects at this elevation had this layering (N, S, and E). We did not investigate West, but it should be the same. The next image is from 7700 feet. Above this elevation, the facets were hard to find and almost non-existent. They produced ECTX results (ie-they would not break).
Photos:
- Mark Staples and Doug Wewer investigating the layering from the 12/27/16 human triggered wind slabs
- Example of natural activity off the Ben Lomond/Willard headwall from Monday night/Tuesday
- High pressure=junk in the valley, SH and near surface facets growing on the snow surface
- West to southwest winds and plumes off the skyline.
