Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Unlikely
- Size
- 3
Dangerous hard slab avalanches failing on a persistent weak layer are unlikely yet possible for people to trigger on very steep drifted rocky slopes with shallow cover and poor snow structure. There is low probability that you could trigger a dangerous, high consequence, 3-feet-deep hard slab avalanche failing on a buried persistent weak layer. Mid-pack weak layers developed during the New Years cold spell, and shallow snow in many areas is loose, sugary, and faceted throughout. Frost or feathery surface hoar and small-grained near surface facets plague the snow surface on many slopes currently, and will likely become persistent weak layers after buried by the next storm.
Chains of well developed, loose faceted snow. Weak sugary snow like this is widespread in the Logan Zone in places where the snow is less than about a meter deep.