Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–3
You can trigger a large and dangerous avalanche on west through north to south-facing slopes that breaks into weak layers buried three to five feet deep. There may not be any signs of instability, like cracking and collapsing, until you trigger an avalanche. You are most likely to trigger one of these slides from a shallower area of the snowpack. If you trigger an avalanche that breaks on the deeply buried weak layers, it may break wider and run farther than you anticipate. Avalanches can also be triggered from the bottom of a slope or from a distance, so pay attention to steep terrain overhead and keep your margins for error wide. Slopes less than about 30 degrees that are not connected to larger, steeper slopes above offer safer riding options.