Persistent Slabs
- Hochgebirge
- Waldgrenze
- Unterhalb der Waldgrenze
- Wahrscheinlichkeit
- Likely
- Größe
- 3
Today, human-triggered slab avalanches failing on a buried persistent weak layer could be large and life-threatening. This week, heavy snowfall and drifting by winds from the west overloaded slopes plagued by widespread buried layers of weak, sugary snow or facets and feathery surface hoar that developed during the prolonged December dry spell.
- Avalanches could be triggered remotely, from a distance, or worse, from below!
- Collapsing or whumpfs and shooting cracks indicate unstable snow.
- Avalanches are possible even when no obvious signs of instability are apparent.
- Exposed slopes, where the wind drifted the heavy new snow, developed dangerous wind slabs that now are overloading buried persistent weak layers. Watch for and avoid stiffer drifted snow on the lee side of prominent ridges and in and around terrain features like sub-ridges, gully walls, mid-slope rollovers, and cliff bands.