Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 3
A persistent weak layer of faceted snow exists about 2 feet below the snow surface. Over the past two weeks it has produced widespread collapsing, a few natural avalanches, and continuously reactive stability tests. In our travels yesterday, Dave and I observed the first signs that this weak layer is gaining strength in some areas. This does not mean we are out of the woods. On the contrary, it means that things are about to get more tricky. When outward signs of instabilty such as collapsing and whumphing are in our face, the danger is obvious. When they aren't present, it can give us a false sense of security. As far as faceted weak layers are concerned, they take a long time to truly go away. We are in the earliest phases of tuning the corner on SOME slopes. Continuing to avoid all slopes steeper than 30 degrees remains the best strategy.
The persistent weak layer problem is not limited to the shady slopes. SE and SW aspects have also have poor snowpack structure. On Wednesday, Dave and I got very reactive test results on a SE aspect at 11,000' (see video below).