Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1.5–2.5
Significant variability in the snowpack exists throughout the forecast zone. The persistent slab problem exists in locations where snow has been preserved since November forming a weak layer that is now buried 2-3 feet deep below firm, cohesive slabs. In general, this weak, sugary snow structure exists above 8300’ and will be most reactive on shaded aspects (NW-N-NE). As this layer trends more stubborn adjusting to the current load, the possibility still exists to trigger an avalanche. The best way to manage this problem is to choose terrain away from steep, rocky, and complex slopes where you are most likely to encounter those thin and sensitive areas of the snowpack. Riding across one of those thin, sensitive areas could collapse the weak layer and trigger a large/destructive avalanche. Hence why previous tracks do not indicate slope stability with this type of problem.
(12/15/2023)
Here is a good example of steep, rocky, and complex terrain where persistent slab avalanches are possible.
Photo: Alex Drinkard