Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2
A persistent weak layer of faceted snow that developed during the cold dry period in mid November still exists on W-N-E aspects. Slopes facing NW-N-E, near treeline and above, are the most suspect. In these areas wind drifted snow has built thick slabs on top of the weak layer. It has been quiet in the backcountry lately. Observers have not been reporting red flags or obvious signs of instability. In my travels yesterday, stability tests continued to show a less sensitive weak layer. Today will be the last day under these quiet conditions. A poor snow structure remains and a powerful winter storm will create dangerous avalanche conditions starting Tuesday night. With significant snow in the forecast this week, deep and dangerous avalanches, failing on this buried persistent weak layer will become increasingly more likely.