Persistent Slabs
N
NE
E
SE
S
SW
W
NW
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
The most dangerous slopes are easterly-facing slopes that sit directly below ridgetop and are receiving wind-drifted snow. Visible snow blowing off peaks or ridgetops is a sign that lee slopes are getting loaded with drifted snow. Another sign that you are on a drifted slab of snow is a harder feel to the snow from sheltered slopes with softer snow.
In sheltered areas, especially steep, open meadows, a weak layer of surface hoar is buried 1 to 2 feet from the surface on northerly and east-facing slopes. You may get collapsing sounds and shooting cracks as a sign that you have found this unstable snowpack. But a lack of these signs doesn't mean it's not there. The only way to know is to dig down and look for this layer.