Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 2–3
A natural avalanche cycle may have occurred over the past 24 hours. There is a good chance of seeing signs of new avalanches in the backcountry today. While yesterday's storm underperformed, some areas received a non-trivial new load of 0.8 to 1.3 inches of snow water equivalent (SWE). This new load will put additional stress on the Jan 2 persistent weak layer (PWL) (buried surface hoar, faceted snow, and/or a crust/facet combo) that has been the main player in recent avalanches in the backcountry. Any avalanches that are triggered today could step down to weak faceted snow located much deeper in the snowpack around the Dec 19 rain crust or the depth hoar near ground level. An avalanche that steps down to either of these deeper weak layers could result in a size D3 avalanche.
Recent avalanches, long cracks in the snow surface, snowpack collapse, or whumpfing sounds are indications of unstable persistent slabs in the immediate area. These avalanches could be remotely triggered from low angle terrain above, below, or off to the side of a steeper slope. If you are encountering any signs of instability, avoid steeper slopes and opt for low angle slopes without steeper connected terrain above or to the side.
(1/11/2024) One of several avalanches remotely triggered by backcountry travelers on Jan 11. This one was remotely triggered by a snowmobile traveling in adjacent low angle terrain north of White Rock Lake near Independence Lake, CA. The depth of this avalanche was due to wind-loaded snow on top of the Jan 2 PWL. Any avalanches today that step down to a deeper weak layer could easily have this amount of depth. Photo: Public
