Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–3
Weak, faceted snow from October exists near the base of the snowpack on most mid to upper elevation slopes facing NW-N-NE-E. Significant storms in December built a dense 2.5-4' thick slab on top of this weak layer. The snowpack is slowly adjusting to the load, and on wind-sheltered slopes where the snowpack is more uniform, triggering an avalanche has become unlikely.
But—there's always a but—in wind-exposed, upper elevation, and alpine areas, the picture is less rosy. These places have two strikes against them. First: the wind over the past several days has continued to add more load to the buried weak layers. And second: in this sort of terrain, shallow spots where you could impact the weak layer are more common.
So why risk it? Safer conditions—and the best powder—can be found on wind-sheltered slopes. In these areas, the weak October snow has had more time to adjust, and you can also avoid wind slabs (Problem #2). Best to let sleeping dogs lie and take our powder hounding elsewhere!
(1/1/2022) This avalanche in Prairie Creek occurred sometime during or just after the Christmas storm. E/NE aspect at 9,500'.