Quick report
Above ~4,000' in the Twin Sister Range today, the snow had some visible wind effect and we observed the crown and debris of a large skier-triggered avalanche on the Northwest face of North Twin. In wind-loaded areas, hand shears produced a fairly cohesive slab atop denser snow/crust. Ski quality was excellent in the morning but notably heavier on our second lap and we observed widespread loose-wet debris in the afternoon on our (north-facing!) exit.
Avalanche
- Size
- D2
- Aspect
- NW
- Trigger
- AR
- Elevation
- 6500 ft
Avalanche appeared to be a wind slab triggered near a rocky cliff band on a 40+ degree, unsupported slope (just off the summit of North Twin). Avalanche entrained significant storm snow across much of the northwest face and ran ~1,200 feet, well into the flat bench at the base of the slope. Unknown date of occurrence, but the debris appeared fresh and was not covered with new snow. Two tracks exited the slide.