Persistent Slabs
N
NE
E
SE
S
SW
W
NW
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
You can trigger a dangerous avalanche that breaks on weak layers and crusts one to three feet below the snowpack surface. These avalanches can propagate widely. You can find these layers on many slopes, but the most dangerous are the ones where recent winds have drifted through lots of snow. Use caution below ridgelines where you find smooth pillows of snow or below cornices. You are most likely to trigger an avalanche from thinner snowpack areas around rocks, trees, and on convex rollovers. Evaluate any steep slope for buried weak layers before you travel on them.