Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 2
A persistent weak layer of loose, sugary faceted snow exists on W-N-E aspects beneath a slab that is 2' -3' thick. This problem is most pronounced on slopes facing NW-N-NE-E near treeline and below where cold temperatures have helped preserve it. Above treeline the weak layer distribution is much more variable and it is hard to track, but where it does exist, wind drifted snow has has helped to overload it. In our travels last week, we experienced localized collapsing near tree line and below on shady slopes and stability tests continue to produce failures in snow pits. As time goes on and things begin to stabilize, outward signs of instability will lessen and we'll be more tempted to venture into steeper terrain. But with the knowledge of what's underneath, it will be hard for me to justify going on to steep, northerly facing slopes for some time.