Persistent Slabs
- Alta montaña
- Límite del bosque
- Bajo el límite del bosque
- Probabilidad
- Possible
- Tamaño
- 1.5–2
Triggering a 1-3 ft thick persistent slab avalanche on buried weak layers (sugary facets, surface hoar, and crust + facet combinations) is still possible. This problem is worst on wind-loaded middle and upper elevation slopes facing NW-N-NE-E. Dry or wet, these are the aspects where you're most likely to trigger a large slab avalanche.
Look for smooth snow pillows, dunes, textured snow surfaces, and cornices as indicators of wind-stiffened snow. You may not see obvious signs of instability, such as snowpack cracking and collapsing, before triggering a slide.
(3/17/2026) A pair of large natural slab avalanches that failed on weak sugary facets buried 2 feet below the surface. N aspect @ 8300'. These probably occurred over the March 14/15 weekend.
Photo: Sawtooth Avalanche Center