Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–3
Buried facets and depth hoar are a concern on the northern half of the compass. Slabs on top of these weak layers average 1.5 to 2.5 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 has become stubborn to triggers, often requiring a thin spot on the slope, such as near buried rocks 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 can be avoided on slope angles consistently less than about 30 degrees and is very unlikely on southerly aspects.
A couple of persistent slab avalanches were remotely triggered in the upper Cement Creek area on Friday, 2/28.