Persistent Slabs
N
NE
E
SE
S
SW
W
NW
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
The most dangerous areas are found near and above the treeline where the wind built cohesive slabs of snow over weaker snow layers. Avoid travel on slopes steeper than about 30 degrees in these areas. You could trigger a dangerous avalanche that breaks in weak snow layers near the ground on northerly and east-facing slopes. Assess the snowpack carefully before traveling on and under steep slopes. Avoid areas beneath ridgelines, cornices, and gullies where you see evidence of drifting such as rounded snow pillows or a hard, sculpted snow surface. You will find safer conditions on wind-sheltered slopes where the snowpack is more than about 5 feet deep.