Persistent Slabs
- Alta montaña
- Límite del bosque
- Bajo el límite del bosque
- Probabilidad
- Unlikely
- Tamaño
- 1–1.5
An extreme wind event last week formed a few thin, hard slabs scattered across all elevations, in concave catchments and behind abrupt transitions in the terrain. Where these drifts formed over facets on colder aspects, you might still be able to trigger one, and they're stiff enough to knock you off your feet. Look for firm, rounded snow surfaces to identify potential features of concern.
Snowfall and wind drifting in early December formed slabs up to a couple of feet thick over facets near the ground. These weak layers are most widespread on the northern half of the compass. Mild weather through the middle of December has helped the snowpack adjust to its current load, and in many areas, the slabs have decayed or been scoured away by winds. The last documented avalanche on these old, weak layers was accidentally triggered on 12/14. Similar instabilities will be very rare, but not impossible.
An example of a thin, hard slab over sugary facets. A few inches of snow and wind on Christmas may obscure the visual clues of older, hard slabs.