Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Unlikely
- Dimensione
- 2–2.5
The Atmospheric River and extended warming temperatures have put the snowpack through the wringer, shaking out many of the weak layers through natural activity. Avalanches are unlikely where a supportable melt-freeze crust exists on the snow surface. However, in steep terrain undisturbed by recent slides, the right trigger in the wrong spot may still cause large avalanches that release on weak layers buried 2 to 3 feet deep. Isolated whumpfing collapses and propagating results are still being reported.
You may trend towards the shaded, high elevation slopes holding both the best snow and most sensitive persistent slab structures. Dig down to look for layers of buried surface hoar and/or facets near crusts before committing to steep terrain. If column tests produce sudden collapses or propagation, step back to lower-angled, simpler terrain.
(3/2/2025) Wide crowns on the east face of Mount Grant. Triggering avalanches like these remains possible today. Photo: Paul Fotter