Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Avalanches continue to be triggered on the persistent, small faceted grains at the old surface which the recent storm snow (16-22") fell upon beginning on Feb 6th. Soft slab avalanches were triggered on this layer yesterday, with a similar example triggered two days ago on Mount Albright in the Tetons. Many other avalanches have been reported, see the Observation section for more. Remember that the weak layer in question is easy to find but unreactive in most pits and is only reactive in specific areas where the right combination of slab character and layer weakness exists. Sheltered areas are not immune to this problem though very steep slopes over 35 degrees, especially wind-loaded ones, are especially prone to avalanching. In every reported avalanche on this layer, no cracking, collapsing or other warning signs have been observed prior to triggering. Now is a great time to view most every slope with some suspicion, follow safe travel protocols and definitely remember this layer when we get more snow and wind.
Deeper in the snowpack, weak snow that formed during a dry period in the second half of January has been buried 3-4 feet deep. This 1/31 layer appears to be dormant after significant testing by water weight, and human and natural triggers.
Foreground: Tuesday, 2/11, Breakneck. Background: Monday, 2/10, Pucker Face. Both of these avalacnhes were humna triggered. Photo: Steph Schmitt