Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Unlikely
- Size
- 2
Poor snowpack structure, comprised of a dense slab over weak, faceted snow still exists in some areas. In specific areas above treeline, the slab is cohesive enough to produce avalanches. The problem with basal facets is that even though it has been a long time since our last avalanche, you can still get surprised. All you need to do is find a trigger point. This is why we have a hard time trusting this setup. While the likelihood has decreased, human-triggered avalanches may still be possible. If triggered, these D2 avalanches will break to the ground, en-training the full depth of the snowpack. Likely trigger points include rocky, radical terrain, steep convexities, cliff bands, and shallow slope margins.
On some near treeline slopes, and many slopes below, the slab has faceted through and has lost all cohesion. This is where you will find the softest snow right now but obstacles are not far below the surface. Looking ahead, this loose, cohesion-less snow will undoubtedly form our next persistent weak layer when snow finally comes.