Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Yesterday, near Concil Mountain, we observed test pits with poor structure in the upper 2 feet of the snowpack which had a couple of layers of buried surface hoar that were failing moderately to hard in compression, but not propagating in an extended column. Kevin and I investigated a snowmobile-triggered avalanche not far from our pit location and got similar test results, but had a propagation saw test propagate after less than half a cut (PST45/100 END) near the crown of the avalanche. The buried surface hoar was visible on the bed surface of the avalanche.
While this problem likely exists on East and Northeast aspects in wind-sheltered terrain, it begs for increasing your margin of error and maintaining good travel protocols, and ensuring that all of your group is wearing a transceiver, shovel, and probe on their person.
(2/6/2023)
Looking at a snowmobile rider triggered avalanche on a NE aspect just North of Council Mtn
Photo: KS