Quick report
I went out and dug a pit for instructional purposes yesterday. After searching for a place with enough snow to actually dig one, I settle on a northeast facing aspect at near treeline elevation that received a lot of shade. While I was expecting a fairly benign and thin snowpack, in this area I found an 85 cm snowpack with a faceted layer near the bottom. When testing the firmness of the layers, this weak layer was easily scooped out with minimal force. The layer did not fracture at all during the conduct of an ECT but when conducting a shovel shear test prior to filling the pit, the layer of concern was the first to fracture and it did so suddenly and all at once. It seems this layer is located only in isolated areas as other individuals digging on different aspects and in more direct sunlight did not find it.