Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 2
What really impressed me from my field outing yesterday afternoon was how sensitive the weak, pre-existing snowpack was to relatively modest snow and water amounts. Numerous bullseye clues were present: cracking, collapsing, and most importantly, natural and easily-triggered human avalanches. Our weak faceted snow preserved on mid and upper elevations facing west through southeast quickly showed its hand, and it was clearly telling us it was going to be very reactive to the load of new snow. The video below (LINK) describes our current snowpack on these slopes:
We can expect more avalanching on slopes harboring the weak faceted snow underneath, especially this afternoon as snowfall and winds increase. One final thought: although we generally think of northerly aspects as where we will find weak snow, the low angle of the November sun expands "northerly", making these early season weaknesses cover a pretty big piece of the compass on the problem locator rose.
This old faceted snow will remain a dangerous weak layer all weekend and beyond.