Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Possible
- Dimensione
- 1–2
Weak facets and buried surface hoar sit below a 2 to 3 foot deep hard slab. The likelihood of triggering a slide that breaks on this layer has been decreasing daily, but it is still possible and the consequences are still serious. Shaded slopes steeper than 35° degree, above 8,000 feet and below the exposed alpine is where you could encounter this problem. Avalanches failing on this layer are difficult to trigger and signs of instability will likely not be present. Be diligent with your terrain assessment and wary of steep slopes where this weak layer exists.
Take a look at this persistent slab avalanche triggered two days ago in Prater Canyon in the Salt River Range. While not in this forecast zone, a very similar snow setup exists and this avalanche is a good reminder that these avalanches can still be triggered.
(2/27/2026)
Recent avalanche near Split Rock. This avalanche was on the smaller side, but if piled up in a creek of depression (terrain trap), it could have still buried a rider.