Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1.5–2.5
The Valentine's Buried Surface Hoar layer, along with weak faceted snow from the January Drought (buried on Feb 8), has been found in the upper 3 feet of the snowpack. If you trigger a slab avalanche on either or both of these fragile weak layers, you will likely produce a large to very large avalanche.
Persistent Slab avalanches can release in surprising ways:
- They can be much wider than expected
- They can break above you and pull into relatively gentle terrain.
- Although unlikely right now, you can trigger them remotely—from flat terrain below, above, and to the sides of steep slopes.
Yes, keep your ears peeled for collapses or whumphs, but don't let their absence allow you into consequential slopes over 30 degrees. Avoidance is our top (and our only) tool when it comes to dealing with a persistent slab.
(2/25/2026) Southeast 8900' Photo: Willie Sloop