Deep Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–3
Our snowpack has a few weak layers right now. These layers are pretty obvious if you stick your pole or probe in the snowpack and feel the changes in resistance as you push down. Triggering these weak layers is getting much more difficult, but if you do you may trigger a large unsurvivable avalanche. Its the classic low probability/high consequence scenerio. The weak layers failed naturally on a lot of steep slopes around December 21st, but not all...not good enough to count on them being gone, so the take home point is you can get away with a lot right now but the land mines might still be out there. The overall strong over weak structure does not inspire great confidence right now in the snowpack.
In the upper 2 feet, crusts, small-grained facets, and degrading surface hoar are present depending on your aspect. Deeper in the snowpack is a lingering layer of loose, larger grained faceted snow that refuses to go away. While this weak layer is getting harder to trigger and slowly gaining strength, the skier triggered avalanches in the backcountry near Tamarack Ski Area this past week demonstrate how touchy this layer still is in some areas. With the overlying slab becoming more consolidated, denser, and continuing to get thicker, the consequences of triggering an avalanche in this layer are going up with every storm.
While the potential for natural avalanches has decreased since our last storm, the potential for skier and snowmobile triggered avalanches remains. Choose your terrain wisely and keep an eye on your partners. Don't ski out of bounds near the ski areas without the proper safety and rescue equipment.
Test pit on Saturday Jan 9th showing weaker structure at the base that has been responsible for natural and human triggered avalanches as recent as Thursday Jan 8th