Persistent Slabs
N
NE
E
SE
S
SW
W
NW
- Alpin
- Limite forestière
- Sous la limite forestière
- Probabilité
- Unlikely
- Taille
- 2
Up high and on slopes facing west, north, and east, avalanches failing on a persistent weak layer are possible in isolated outlying terrain where previously wind-drifted snow overlies weak, sugary snow from November. Dangerous hard slab avalanches are increasingly unlikely as the shallow, sugary snow from November is buried and pressed into terrain anchors by a deep layer of heavy, hardening snow.
- Unlikely avalanches failing on a persistent weak layer might still be triggered remotely, from a distance, or below.
- Cracking and collapsing (or whumpfs) are definite signs of instability, but they may not be present when avalanches occur.
- Avoid stiffer, drifted snow on the lee side of prominent ridges and in and around terrain features like gullies, sub-ridges, scoops, mid-slope rollovers, and rock outcroppings or cliff bands.