Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 2
Several very large avalanches which failed during the wind and snow event hit Highway 20 again on Thursday. Check out the photo below. This occurred during the height of the storm, but we are not too far out from that yet, so continue to exercise caution in steep terrain and beneath runouts of large avalanche paths.
There are a number of underlying layers of concern which slab avalanches could fail on, such as a sun crust from Wednesday’s intense sun on steep southerly slopes, or a layer of graupel in other areas. You may find slabs 6 inches to several feet thick. Previously, strong winds redistributed snow into touchy slabs. These will most likely fail in gullies, beneath rock bands, below cornices (which are getting very large) and under ridgelines. Your added weight makes an avalanche occurring on these steep slopes likely. Search for pillow-like drifted snow deposits and feel for stiffer snow as you travel, and avoid these areas on steep slopes. Dig down a couple feet and investigate whether any layers fail easily. Start in lower angle terrain and small test slopes before exposing yourself to steeper areas.
(2/21/2021) A skier intentionally triggered this slab avalanche in Swift Creek on a NE aspect at 4500ft. Photo: Phil Straub