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 treeline are the most problematic. This is where winds drifted recent snowfall into varying thickness slabs above well-preserved weak snow layers. Shallow avalanches in the recent storm snow may break deeper where older, weak snow layers are less than about two feet deep – slab margins, near exposed rocks and trees, and on steep rollovers. Move to lower angle slopes if you see cracking in the snow or the snow surface gets stiffer – especially if it looks smooth and rounded. Safest travel options exists below treeline.
Sun and warming temperatures may trigger sluffing of the recent snowfall on steep, sunny slopes at upper elevations.