Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Unlikely
- Size
- 1–2
Some starting zones on northerly and northeasterly aspects still have a weak layer near the base of the snowpack. Recent observations indicate that the reactivity of this weak layer, found near ground level, is diminishing. The distribution of this weak basal layer may vary significantly, even in adjacent locations.
While triggering an avalanche of this type will be unlikely, the consequences will be severe. The only way to determine the presence of this problem is to inspect the snowpack by digging to the ground, performing stability tests, and examining the structure.
More snow and wind this week may wake up this dormant problem. The last known avalanches resulting from persistent weak layers (near the ground) occurred during the MLK Storm Cycle of mid-January. They were natural avalanches of size ~D2.