Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
If triggered the persistent slab is very likely to steep down to the deeper instability and involve the entire winter's snowpack.
Although the hazard has decreased slightly, forecasters are still very concerned with the snowpack structure. The bottom half of the snowpack is very weak, and full-depth avalanches will remain a real concern for some time to come. Very conservative route selection is still in order.
If triggered the persistent slab is very likely to steep down to the deeper instability and involve the entire winter's snowpack.
This layer will be easier to trigger from thin, weak shallow areas. Wide propagations are possible.
Nothing new observed today.
The snowpack has seen very little change in recent times. The mid-December surface hoar layer down 30cm at Treeline continues to react as a persistent slab with compression tests in the moderate range. Below this, the remainder of the snowpack is heavily facetted. Any avalanche triggered in the upper snowpack will almost certainly step down to the ground.
Despite a slight improvement in the hazard, forecasters are approaching all terrain conservatively and do not have much confidence in the snow pack, as it's one of the worst we've seen in many, many years.
Thursday will be very windy with a mix of sun and cloud. Ridgetop temperatures should reach -5C as a high. A trace amount of flurries are possible for Friday with rain at lower elevations.
More details can be found in the Mountain Weather Forecast.