Persistent Weak Layer

Avalanche hazards were less obvious today than two days ago on Dec. 24, when we experienced widespread cracking and collapsing. However, I believe that the same base instability is there and unchanged, just less responsive since it is buried under more snow. The snow from the last two storms seems to have bonded well. When digging our pit and performing stability tests, this snow formed one big chunk that moved together and could be picked up. At least on the N aspects, I think we can consider it one big slab moving forward. On the protected N aspect where we dug, this slab is now sitting on top of a thin, breakable crust with some small facets at the interface. This crust in turn sits on a layer of buried near surface facets, which is supported by another, thicker crust separating the old depth hoar. In our pit, we had several columns that failed on isolation. When we could actually isolate a column, it took a little effort on a compression test (CT 11), but popped out relatively easily on a shear test with Q2. The snow consistently failed at the interface of the new slab and thin crust, and then immediately stepped down through the buried near surface facets to the deeper, harder crust. Overall, it seems that we are moving toward a sleeper hard slab problem that will likely not be remedied anytime soon. Barring any surprise storms in the near future that could clean out some of the snowpack in problem areas, I anticipate conditions moving toward low probability / high consequence.