Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 3
Hard slab avalanches up to 3 feet deep remain possible, but are becoming less likely to trigger. This problem is most relevant on steep, wind-drifted slopes at upper elevations and on select mid-elevation terrain features where poor snowpack structure still exists. Weak, faceted snow from November is now buried beneath a thick crust, or multiple crusts, along with dense, damp snow and the most recent snowfall.
- Collapsing—seen as shooting cracks or heard as audible whumpfs—is a clear sign of unstable snow, though it may not always be present.
- Avalanches might be triggered remotely (from a distance or below).
The likelihood continues to decrease overall, especially as the weak grains become damp, wet, or locked into a crust near the ground. Even so, the structure is still there, keeping some uncertainty in the system. Treat steeper slopes with respect, and continue to give this layer the space and caution.
Video from the Northern Bear River Range in southern Idaho shows no signs of instability as of yesterday, though this area has generally seen higher snow totals throughout the storm cycles. The Northern Bear River Range, including southern Idaho, has a somewhat deeper and more stable snowpack, with more uncertainty remaining at the southern end of the range, including Logan Canyon.