Deep Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Unlikely
- Size
- 2–3
The Summit Lake zone has received 1" snow in the past 25 days. There may be isolated slopes where a person can trigger a small wind slab avalanche in previously wind-loaded terrain, but these are limited by the amount of soft snow available to be blown around. The bigger concern is the small chance of triggering a large avalanche on weak snow buried deeper in the snowpack. Mik found weak structure on Summit Mtn. on Thursday (details here), which confirms what we have been seeing for most of the season.
For now we are in a bit of a holding pattern with this problem. It is unlikely someone will trigger an avalanche deeper in the snowpack until we see another major loading event, but that chance still exists. Keep this in mind if you are moving into steeper terrain, and consider avoiding slopes with higher consequences if an avalanche should occur. This could be larger start zones, or it could be slopes with cliffs, trees, or gullies in the path.
Glide Avalanches: We're continuing to see glide avalanche activity throughout the forecast area. These avalanches are large and unpredictable, so the only way to manage this problem is to avoid spending time under open glide cracks.
(2/20/2025)
Snowpack at 2,400' on Summit Mountain. Poor structure exists with a weak layer of facets below a large 3' slab.
Photo: Mik Dalpes