Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 3
The primary concern is triggering a large and unsurvivable hard slab avalanche on a persistent weak layer of faceted snow, which is now 2-5 feet deep. This weak layer formed during a dry period in December and got buried on January 4th. Over time, this unstable combination has become more stubborn but remains highly dangerous, and just as deadly. Though the likelihood is slowly decreasing, the consequence remains just as high.
Beyond the highlight reel avalanches, there are less obvious yet just as significant avalanches that caught our attention last Thursday and Friday. These persistent weak layer (PWL) avalanches are away from the ridgelines, occurring within mid to low elevation bands, yet they are large enough to pose a serious threat of catching, carrying, and burying you. Continue to pay attention, as slope angle remains a crucial factor.
Thinner snowpack areas may be particularly suspect. Remember, avalanches can be triggered from a distance or below.