Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Very Likely
- Size
- 2–3
Today's message is simple: STAY OUT OF THE WAY! Dense snowfall (Storm Totals page) and wind (Mountain Weather Forecast) are pushing the snowpack over the edge on many slopes. What should you expect to see out there?
- Large, destructive avalanches are very likely to release on their own (natural avalanches). Some may be large enough to break trees.
- Remotely triggering slides from below, above, and to the sides of steep slopes is likely.
- Smaller wind slab avalanches that release near ridgelines could "step down", failing on layers deeper in the snowpack and becoming much wider than the initial avalanche.
Build a lot of extra safety margin into your travel plans today. The Lake Ck avalanche (photo right/below, click here for video) that released Sunday or Monday is over a quarter-mile wide and should be treated as foreshadowing, not as an outlier event.
(1/11/2021) Very large persistent slab avalanche on the headwall at the back of Lake Creek. Crown is at least 1000' wide. Based on earlier observations it likely failed between 1/10 and 1/11.