Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
You can trigger a dangerous avalanche on slopes facing west through north to southeast near and above treeline. At higher elevations, you may trigger a small avalanche in wind-drifted snow; however, the greater risk is triggering a large avalanche that breaks on a weak snow layer one to three feet deep and grows large enough to bury you. You are most likely to trigger one of these dangerous avalanches where it’s easier to impact the weak snow layer—near treeline, where the weak snow is less deep and the overlying snow is softer, or above treeline along the edges or bottom of a slope, where most of the snow is firm and wind-affected, but the weak layer is more vulnerable near the slope’s edge. For safer travel, seek wind-sheltered terrain below treeline.