Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 2–3.5
Weak facets and collapsible crusts are widespread on the northern half of the compass and on some sunnier aspects at high elevations. Recently formed slabs on top of these weak layers average 2 feet thick in wind-sheltered terrain. Slabs are thicker and harder in wind drifted terrain and can step down through older slabs to the ground. This problem is easy to trigger in some shallower areas, and in deeper areas, it may require hitting a thin spot on the slope, such as near buried rocks, trees, or where slabs thin from wind effects. Avalanches can break widely across multiple terrain features and be remotely triggered from flat terrain near or below steep slopes without warning signs. The problem is less common on south and southwest aspects, and can be avoided on slope angles consistently less than about 30 degrees.
These destructive persistent slabs ran sometime around February 18th or 19th on Schuylkill Ridge.