Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–3
Recent avalanches: We got reports of a snowmachine-triggered avalanche lower down in Warm-Up Bowl on Seattle Ridge last Thursday (1/22) that looks like it released on the December Facet layer. It's been 5 days since a large remote-triggered avalanche on Sunburst, which wiped out several sets of recent ski tracks.
We are entering a new, more stubborn phase of this persistent weak layer, where avalanches and red flags are starting to become less common, but the potential for triggering a large and dangerous avalanche 2 to 4' deep still exists. When the snowpack is giving us less direct feedback, it can be tempting to start edging back into steeper terrain. But even for seasoned avalanche pros, it is impossible to predict when and where the next big avalanche on this weak layer might be triggered. The only reliable way to avoid the potential for triggering a dangerous avalanche on the December facet layer is to stay patient and stick to low-angle terrain. Remotely triggered avalanches have been especially common on this weak layer, which means you could trigger an avalanche from low-angle terrain onto connected steeper terrain.
The 1 to 2" of new snow expected today is not going to add enough weight to really stress our current snowpack. However, throughout the week, we are expecting snowfall to continue to pile up, and this incremental loading will eventually tip the scales and make the weak layer more reactive to human triggering and potentially cause natural avalanches. Stay tuned to see how these storms roll in and how much new snow we get this week!