Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2
A classic setup of strong snow over weak snow is developing on upper elevation, northerly aspects that retained snow from October. This October snow has become loose, weak, and sugary, or as we say, faceted. This faceted snow has formed a persistent weak layer at the base of the snowpack. Recent and wind drifted snow has formed a dense slab on top of this weak snow creating an unstable situation, and human triggered avalacnhes up to 2' deep are likely on steep, northerly facing slopes at mid and upper elevations.
Extended column test illustrates the weak layer where a slab avalanche is likely to fail.