Persistent Slabs
- Hochgebirge
- Waldgrenze
- Unterhalb der Waldgrenze
- Wahrscheinlichkeit
- Likely
- Größe
- 2
2 to 4-foot storm slabs that have been building over the last five days have greatly stressed the faceted weak layers deeper down in the snowpack. These persistent weak layers will need time to adjust to this added load before we start to see faceted weak layers start to heal and strengthen. There are several faceted weak layers of concern in the snowpack with the most likely weak layer to trigger being the buried near-surface facets that formed during the 3 week high-pressure period before these storms. Below treeline, slabs rest on top of an entirely faceted snowpack to the ground. A persistent slab avalanche that initially fails in an upper faceted weak layer has a chance to step down into deeper faceted weak layers creating a larger unsurvivable avalanche.
Pay attention to obvious signs of instability like collapsing and shooting cracks. You can trigger a persistent slab avalanche from the flats below or adjacent slopes. Stay off of or underneath slopes that are greater than 35 degrees as we may see avalanches running long distances today.
Wide propagating slabs below treeline failing on the faceted weak snow that existed prior to the storm.