Persistent Slabs
- Hochgebirge
- Waldgrenze
- Unterhalb der Waldgrenze
- Wahrscheinlichkeit
- Unlikely
- Größe
- 2
On a regional scale, persistent slab avalanches have become unlikely. Most data targeting the persistent weak layer (Dec 11 facets) indicates it has adjusted to the current load. No known avalanche activity has been reported on the old weak snow since before the last storm on Jan 6. Further investigation of 2 large avalanches reported earlier this week found that one of them was a case of mistaken identity and was not actually an avalanche. The other likely was not what it seemed either. The last reported whumpfing on this layer came from Pickett Peak on Jan 6. While some snowpit tests continue to yield unstable test results in some places, the majority of them do not indicate instability. The unstable results continue to come from areas with a shallow snowpack like places near Carson Pass and Ebbetts Pass and lower elevation areas in other parts of the forecast region. Uncertainty about this problem still exists and while unlikely, a persistent slab may not be impossible on an isolated terrain feature.
Gather information about whether or not old weak snow exists below the surface by probing and digging into the snow and looking for any signs of instability while traveling. Finding unstable snowpit test results or other signs of instability including whumpfing or cracking could indicate you are in one of the isolated areas where an unlikely but not impossible persistent slab might be hiding. If you find yourself in one of those areas, step back and use terrain to avoid the problem by traveling on slopes less steep than 30 degrees not connected to steeper slopes.