Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Very Likely
- Size
- 3
Thanks to Bo for the observation from Soapstone. Bo's comments fit the bill... "Remotely triggered from flat ground 50 feet from the base of the slope. The avalanche broke along a cliff band at the top of the hill and ran about 200 feet where it piled about 15’ deep in a terrain trap gully at the base of the slope. Collapses had been happening all day so we knew how unstable the snow was but was surprised to see such a large avalanche triggered from a long ways away."
The big ticket today... avoid being on, under, or adjacent to steep slopes.
When I think of the kind of terrain where I could trigger a deep, dangerous avalanche today, places like Currant Creek Peak, Heber Mountain, Murdock Bowl, Yamaha Hill, Double Hill, Moffit... yeah, they all come to mind. It's exactly the kind of terrain where we could be carving deep trenches in the flats but connected to steep terrain above us, trigger a slide from the bottom of the slope, which in turn, knocks the entire roof down on top of us.
Here's the setup- a persistent weak layer of near surface facets that formed over the long stretch of dry, January weather is now protected and preserved beneath our most recent storm. On mid and upper elevation polar slopes, this weak layer is buried over 3' beneath the snow surface, is reactive to our additional weight, and can be triggered remotely or from a distance.... it's game on!
In addition to recent avalanche activity, we're noticing lots of red flags, like shooting cracks and collapsing sounds, which are huge red flags and obvious clues to unstable snow.