Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–3
It's been two weeks without an avalanche, substantial loading, or notable snowfall. So why are folks just now cautiously "stepping out" into shady, consequential avalanche terrain?
- The Weak Layer: Weak, sugary faceted snow exists near the ground on many upper elevation slopes as well as shady NW-N-NE-E facing slopes at middle elevation. This layer is widely distributed and is not strengthening quickly in this zone.
- The Slab: The 2.5-4 foot thick slab above the weak snow is thick enough to produce large avalanches that could bury people but thin enough that skiers and riders can impact the weak layer and possibly trigger slides.
The nature of a persistent slab problem is in the name. This problem will take time to heal and will require patience to manage. Triggering a large, persistent slab avalanche is still on the table. To reduce the chances of finding trouble, avoid "prime time" slope angles (35-45*) in rocky, wind-affected terrain (see photo).