Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–2.5
1 to 2 feet of new snow has accumulated since March 3rd. That snow has settled into a slab over a variable distribution of small facets, surface hoar, and collapsible crusts. This new persistent slab avalanche problem is the most reactive on previously wind-loaded terrain. The avalanche problem becomes more spotty in distribution on lower-elevation wind-sheltered slopes. Consider evaluating the slab characteristics over these persistent weak layers in your area, or more simply, manage the potential avalanche problem through your terrain choices. Such as choosing lower-angled slopes and/or avoiding slopes with terrain traps like rocks, trees, or gullies.
Avalanches can also break on weak layers in the middle of the snowpack (the January/February drought layer) or at weak layers near the ground. The snowpack is often shallower in the Southeast Mountains, which could make it more likely for you to trigger an avalanche on deeper weak layers. An avalanche that fails in the middle or at the bottom of the snowpack would certainly be large and potentially hard to survive.
A snowmobile triggered slab avalanche in the Kebler Pass area.
March 8th. Photo: Care Flight