Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–2.5
You can trigger an avalanche on steep, recently drifted slopes at upper elevations. Look for and avoid bulbous pillows of snow below ridges, in gullies, and behind convex rollovers. Cracking in the surface snow signals that you can trigger a slide. Snow that sounds hollow or drum-like as you travel over it is another warning sign.
Avalanches that break near the surface will be small, but they can step down to weak layers 2 to 3 feet deep. In areas with a shallower snowpack or on slopes already avalanched this year, avalanches could even step down to the ground. The new snow makes these areas harder to identify, but avoid the edges of terrain features or areas with variable snow cover and exposed obstacles. Rocky, steep, shady slopes are the most likely places to trigger a deeper avalanche.
You can find safer travel on low-angled and wind-sheltered slopes.