Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Possible
- Dimensione
- 3
Upper elevation slopes facing north and northeast remain the bull-eye terrain for harboring weak faceted snow, and are where dozens of avalanches have been triggered in the backcountry or at resorts. The faceted snow near the ground, and it formed when a shallow layer of October and pre-Thanksgiving snow sat around for weeks.
The pattern is more complex on the mid elevation shady slopes and on upper elevation NW, W, E and SE facing slopes, with some slopes lacking facets and others having large collapses and recent avalanches. If you want to go steep on these slopes, do some research - find a representative lower angle slope, get out your shove and dig down to the ground, looking for facets. Below is a great video by Quinn Graves and Bo Torrey showing unstable results on a northeast-facing slope at 8,500’, indicating stay off steep slopes of a similar aspect and elevation.
The past week’s avalanche roses illustrates how “persistent” or slow to strengthen the weak layer is.