Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Possible
- Dimensione
- 1
There is a lot going on in this photo but yesterdays avalanche illustrates pockety, persistent slab avalanches are in fact a player and reactive to our additional weight (via A. Richards).
Consistent, yet variable winds have welded stiff, hard slabs in place and that'll feel solid under our ride, but the problem is... this setup rests above a sugary layer of faceted snow that formed during the recent stretch of high pressure. We forget about weak layers, but the snowpack has a great memory. (Learn more about it here, and why it's important to pay attention to surface conditions.)
Above treeline, on steep, wind-loaded slopes, specifically those with with an easterly component, hardened slabs living above faceted snow are reacting to our additional weight well after they formed. This is why we've transitioned our wind-drifted snow problem to a persistent weak layer. While the chances of triggering this avalanche problem are decreasing, if you're getting after it on sustained, steep terrain in the alpine, remember even a small slide in consequential terrain could turn nasty if it strains us through trees, rocks, or over cliffs.
Fortunately, we can avoid this problem by seeking wind sheltered terrain out of the alpine where we're greeted with more straight-forward avalanche danger and protected, cold, recycled powder.