Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–3
This persistent slab problem is becoming slightly harder to trigger with time. But, it will also be extremely difficult to determine which slopes may slide and which won't and hitting the wrong spot can result in a very large and destructive avalanche . The Early February Crust (EFC) harbors weak, faceted snow and is now buried underneath a dense 2-4 foot thick slab. This recipe for avalanches exists on most middle and upper-elevation slopes.
This persistent problem requires patience and strict management. These slabs can trigger in surprising ways. You can trigger them from flat or low-angle terrain long distances away from steep slopes, and they can break far above you. Before triggering an avalanche of this type, you may or may not receive any direct signs of instability. Therefore, your best strategy to avoid triggering a large, unsurvivable avalanche will be to avoid travel on or below slopes greater than 30 degrees.
(3/2/2024)
You can still trigger very large avalanches like this example from last weekend.
6600 ft on a NE aspect on Darland Mtn.
Photo: Katie Warren