Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Possible
- Dimensione
- 1–2
Our main concern today is the potential for human triggered avalanches on lingering pockets of buried surface hoar about 2' deep or deeper above 2500'. These weak layers were buried in mid-December and due to the recent prolonged stormy weather we don't have much information about how widespread they are or if they are still possible for people to trigger. Please send an observation if you get out in Turnagain Pass.
We recommend evaluating the snowpack before committing to steep slopes by looking for red flags, jumping on test slopes, and using hand pits or snowpits to test for weak layers buried in the snowpack. These can be hard to see in the snowpack, but if you get a clean break in a hand pit or snowpit it is worth looking carefully at the snow grains at the fracture interface to try and spot buried surface hoar. You can always stick to lower angle terrain to avoid this problem entirely.
Cornice Fall: The holiday storm built fresh cornices which could be sensitive to the weight of a person. Remember to give cornices a wide berth if you are traveling along ridgelines.
Example of buried surface hoar layer on Seattle Creek from Dec 19th. This layer now has the snowfall from the holiday storm on top of it.
Photo: Andrew Schauer