Gunnison
AvalancheZach Guy · Jan 5, 2015 · Gunnison
Weather
Broken skies becoming scattered to few in the late afternoon. Moderate to strong W/SW winds at ridgelines blowing snow. In valley bottoms light to moderate winds were also drifting snow.
Snowpack
Toured in the Schuykill area observing the persistent slab structure through different elevation bands: Below 9,600ft Persistent slab structure was very weak with a faceting slab. A few collapses but no shooting cracks. ECT results were non-propagating slab fractures (ECTN, moderate to hard). Areas with previously wind hardened snow were most suspect. 9,600ft to 10,000ft The slab gained enough strength or cohesion (F+ to 4F, 60 cm thick) to produce a shooting crack on a 33 degree slope after a collapse. 10,000-11,300 Persistent Slabs became quite with no collapsing. HS averaged 100-140cm, slabs about 70+ cm thick. The 12/13 interface was obvious in the snowpit wall and still very weak facets, but ECT tests did not produce any results (ECTX), Compression tests produced sudden collapse results on the 12/13 facets.
Avalanche
Shallow windslabs were touchy at ridgeline on Northeast aspects near treeline. Two skier triggered windslabs generally 2-4″ deep but up to 6″ in places. 30-40ft wide and one ran 500 vertical feet but was still a D1. We watched a natural avalanche mid day on a NE aspect near treeline. Appeared to be a shallow windslab that then stepped down to a 100 ft wide persistent slab, maybe a foot or two deep, but we observed this from valley bottom. The whole mess ran 1,000 vertical feet and was large enough to bury a person. SS-N-R1-D1.5-O. That slope had slid previously on the Dec 13th facets in mid-December. Lots of evidence of widespread avalanches during the meat of the avalanche cycle back in late December.