Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–3
You can find buried near-surface weak layers on many slopes that face west through northeast to southeast. These layers are becoming harder to trigger, which makes them scary. You will most likely not see any signs of instability, such as cracking or collapsing, before you trigger an avalanche, and multiple people can travel on a slope before someone finds a weak spot and brings the whole slope down. It can be difficult to identify and assess the strength of these layers. If you are uncomfortable doing that, you can always stick to slopes with a slope angle of less than about 30 degrees.
You can also trigger avalanches in the recently wind-drifted snow at upper elevations, especially below easterly-facing ridgelines. If you trigger a small avalanche in the wind-drifted snow, it can step down to these near-surface weak layers, resulting in a large, dangerous avalanche.