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 in wind-drifted snow that is resting on older, weak snow near the ground. Suspect areas are steep slopes below ridgelines, sides of gullies, and steep rollovers. Watch for signs of drifting in the surface snow like smooth, rounded pillows. Stiff, hollow-sounding snow is a sign you have ventured onto a dangerous slab. If you see signs of instability such as cracking or collapsing, move to slopes less than about 30 degrees.