Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Unlikely
- Size
- 2–2.5
Other than a few photographs of a collection large crowns on the north side of Mt Pilchuck, we know very little about the current state of this problem in the West Central zone. Here’s what we do know.
- Weak snow facets, sometimes with a thin crust, were documented prior to the last storm.
- This snowpack structure is incredibly similar to other NWAC forecast zones.
- These weak layers should be most common on shaded aspects.
- There is no easy way to assess a slope’s stability.
- The further we get from the storm, the less likely an avalanche may become, but the consequences are the same.
You’re most likely to trigger an avalanche in areas where the snowpack is thinner such as near rocks, along convexities, or on unsupported supported slopes. These slides may need a bigger trigger like a group of people or a smaller avalanche to fail. The only way to totally manage this issue is avoidance. Fortunately, there's lots of soft snow out there on other slopes.
(2/9/2025)
This slew of natural avalanches in the West Fork of Swift Creek/West North were reported on Sunday. The time of occurrence and weak layer are hard to pin down. Whatever the details, it's proof the layering is still out there to produce slab avalanches. North aspect at 5500'.
Photo: Andrew Richardson