Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1.5–3
In the last week there have been numerous avalanches that have failed on weak snow formed in January. This weak layer exists above 8,000 feet on slopes that face west through north through east. These are hard slab avalanches, breaking 2 to 3 feet deep, that can be triggered by the weight of a rider, or from a distance, so give steep terrain a wide berth. Even smaller slopes around creeks and in the trees can produce avalanches if they are steep. As we move farther away from the last loading event, signs of instability such as cracking or collapsing may not be present, but consequences are still high. Avoidance is the best way to deal with this problem as persistent slab avalanches are not manageable.
(2/26/2026) Photo: Jerry Zimmerman
A large avalanche that was remotely triggered.