Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1.5–2.5
Large and dangerous avalanches breaking into old weak layers are a real concern for both human triggering and natural avalanche activity today. Any natural avalanche activity is expected to be confined to terrain with active wind-loading, while this avalanche problem will be the most sensitive to human triggering on northerly to easterly facing slopes. Slabs are typically 1 to 2 feet thick below treeline and grow larger and even more dangerous in wind-loaded terrain; a few could be up to D3 in size. These avalanches have the potential to break wider than you expect, they can be triggered from flat slopes below steep terrain, and avalanches could further run well into low-angled runout zones.
This is a 2.5-foot thick slab that was remotely triggered yesterday in Washington Gulch.