Persistent Slabs
- Alta montaña
- Límite del bosque
- Bajo el límite del bosque
- Probabilidad
- Likely
- Tamaño
- 3
The past week of heavy snowfall and strong winds continue to overload a buried persistent weak layer of faceted snow down near the ground. This layer exists on mid and upper elevation aspects facing west through north and east. Any avalanche failing on this layer may break down 2-4' deep (possibly deeper), propagate hundreds of feet wide, and run downhill thousands of feet. While the avalanche danger dropped to considerable today, the consequences remain the same; these are large, deadly, and destructive avalanches.
A few words of caution:
- Obvious signs of instability may not be present today: you may or may not see or experience shooting cracks or audible whumping. The danger still exists.
- Tracks on the slope offer zero signs of stability. Avalanches will take out multiple existing tracks.
- You can trigger these avalanches remotely (from a distance) or from below. Give ridgetops a wide berth.
- Any fresh wind slab or new snow avalanche may step down into this older layering of weak snow.
We are on the back end of the parabola as shown below. While we may not be seeing as many obvious signs of instabilities like cracking, collapsing, and recent avalanche activity. The avalanche danger still very much exists. Over the last five days, the danger was very obvious, with high winds and new snowfall. Today that avalanche danger may not seem as obvious, and I fear that people may push out onto steeper west through north through east-facing slopes, get away with it, and think that we are in the clear. We are not in the clear. This avalanche problem is the real deal and should be avoided with large safety margins. Avoidance is the key.
