Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Unlikely
- Size
- 1.5–2.5
The upper snowpack is gaining a lot of strength. Although it is unlikely, triggering a persistent slab avalanche 2-3 feet deep is not completely impossible today as thin spots near rocks and trees may be more sensitive, and most notably temps, Sun and human triggers can get the upper snowpack moving and cause a step down to deeper weak layers and create a large avalanche, especially in steep, wind-loaded terrain above 7000'.
This link to our observation page shows the breakdown of instability and recent avalanche activity during the past week. We've observed several large, natural avalanches within the past 7-10 days. Instability peaked earlier this week. As the name implies, persistent slab problems tend to persist for a while even after instability has peaked. All of these persistent slab avalanches failed above 7000' on N, NE, and E facing slopes.
(1/29/2024) Shaw Twin Ridge ENE 7437FT with 4'5" snow depth.