Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Likely
- Dimensione
- 2
A dense cohesive slab now exists over top of a pre-existing layer of weak, faceted snow that has been sitting around since October. This layer is widely distributed near treeline and below on all northerly aspects as well as on some west and southeast facing slopes. Above treeline, distribution is more spotty due to variable snow cover caused by windy periods during the long dry spell. Regardless, all steep slopes on the north side of the compass should be considered very dangerous, and this persistent weak layer problem will be with us for some time.
The snowpit diagram below illustrates the current structure of strong snow over weak snow. On top you can see the dense slab created by the recent heavy snow. Underneath is the weak, faceted snow, with the red line indicating where we got failure in an extended column test (ECTP 16). A layer of deteriorating basal ice makes up the bottom 5 cms.