Northern San Juan

Avalanche

Mark Gober Ann Mellick · Jan 11, 2016 · Northern San Juan

Weather

Clear, cool, breezy. Light to moderate wind loading happening. Winds strengthened through the day. Winds primarily affected terrain above treeline, but became more of an issue in open ares below treeline as the day progressed as well.

Snowpack

Pit was dug on SE aspect (see attached pit graph). No failure with ECT and a CT28 Q2. Christmas slab was a meter thick with 20 cm new snow on top. Seems it would be tough to trigger but if so, it would be a large avalanche. New wind loading is the main topic now though. Fresh wind slabs are being deposited on southerly slopes currently. These proved easy to trigger by our little test slope (see pics). While wind was primarily affecting terrain just below ridgelines, it was also stiffening surface snow and forming 1"-5" surface slabs in open terrain lower down. ---- Overall, we remain in a low likelihood, high consequence pattern with stout slabs sitting on facets in areas that have not yet slid this year. The most likely place to trigger a slide is on recently wind loaded terrain above treeline.

Avalanche

Short pitch off a ridge line above tree line. Recent wind loading was the cause