Deep Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–3.5
With winds expected to back off today, there will be less concern for natural avalanches on buried weak layers caused by wind transported snow. However, human triggered avalanches remain possible on slopes that were recently loaded by wind transport. Deep persistent avalanche problems are tricky because they tend to give no feedback in terms of red flags and are usually triggered from a thin spot in the snowpack near rocks. Often there can be multiple tracks on the slope before an avalanche is triggered.
Given the current snowpack setup and recent wind loading, we recommend being patient and giving the weak layers some time to adjust to the redistribution of snow the past few days. You can avoid this issue by sticking to lower angle terrain or staying at lower elevations. If you are venturing onto steep slopes choose safe, low angle, up routes, and travel one at a time in terrain greater than 30 degrees.
Cornices along ridgelines and dry loose avalanches on steep slopes are additional hazards to look out for. As the surface snow turns to facets in the cold temperatures dry loose avalanches can start to gain more volume and run faster.
Glide avalanches also continue to be a concern. We have observed several glide cracks continuing to open up since the last major storm and recommend trying to avoid traveling underneath glide cracks whenever possible.
