Avalanche
- Slab Width
- 152 m
- Weak Layer
- Facets
- Trigger Type
- Natural
- Avalanche Type
- Hard Slab
- Slab Thickness
- 122 cm
- Trigger Detail
- Cornice Triggered
- Start Zone Aspect
- Northeast
- Avalanche Problem
- Persistent Weak Layer
- Start Zone Elevation
- 2987 m
All are estimates. Natural cornice failure due to strong winds seems most likely. Did not access crowns due to overhead hazard.
Strong southwest winds on Tuesday Jan 14th likely provoked a large natural cornice fall which in turn triggered a size 2 wind slab that in turn stepped down to near the ground. Arrows point toward grass/shrubs pushing through old snow near the ground. Repeater. Original avalanche during the Thanksgiving Cycle - Thursday - Thanksgiving, November 28, 2019 - as remotely triggered/reported by Mark White. Based on amount of snow on the bed surface, the avalanche likely ran during frontal passage just after noon.
Had been concerned - with the 60-100" (3.5-6.3" SWE) since New Years along with the strong SW winds that some repeaters might come back to life. I suspect that there may be a few more out there. Seems like the major window was yesterday/Tuesday and perhaps tomorrow/Thursday with the strong winds...and then may prove more stubborn in the days ahead.
Forecaster Comments: Thanks to all that submitted info regarding this avalanche; we could save only one observation for our record keeping.