Persistent Slabs
N
NE
E
SE
S
SW
W
NW
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Wind-loaded slopes and terrain features near and above treeline harbor cohesive slabs over weak layers in the upper snowpack. Recent strong winds built varying thickness slabs, and you are more likely to trigger an avalanche where the overlying slab is thinner – near exposed rocks and trees, on steep rollovers, or beneath ridges and cliffs. Shallow avalanches may break deeper where older, weak layers are less than about 2 feet deep. Avalanches on previously drifted northerly and easterly-facing slopes will be larger. You can find safer travel options below treeline, or on lower angle, wind-sheltered slopes.