Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2
Human-triggered avalanches failing on persistent weak layers continue to be a concern on northerly aspects above treeline, where old, hard slabs of wind-drifted snow rest on weak, faceted snow. The primary layer of concern is a faceted layer that formed near the snow surface before the January 23rd storm. Multiple periods of strong winds have since built stiff slabs on top of this weakness, and human-triggered avalanches 1–2 feet deep remain possible. While less likely, avalanches failing on this layer could step down into deeper weak layers in the snowpack, producing a much larger and more dangerous slide.
Given these conditions, upper-elevation, wind-loaded terrain continues to warrant caution. Avoid steep slopes just below ridgelines where smooth, hard slabs of wind-drifted snow are present, especially if the snow feels hollow or sounds drum-like underfoot.
