Northern San Juan
AvalancheAnn Mellick · Jan 18, 2016 · Northern San Juan
Weather
Mostly sunny and mild in the AM with rapid transition to overcast between noon and 1 PM. Wind westerly/10-20+ ridgeline, air temp 33 (0C). Snow moving in the alpine.
Snowpack
Snowpits showed multiple weak interfaces on east and southerly terrain- all of which were crust/facet combinations. Failures were clean and fast and were initiated with low test scores. (see attached pit) Failure at one of these layers would almost certainly initiate failure lower down in pack (as evidenced by large propagating slides on south side of Commodore ridge as well as in Commodore Gulch proper). Snow is stronger on northerly slopes below treeline- fewer weak interfaces. Supportive with rapidly settling storm snow.
Avalanche
Lots of slides in a small area in and around Commodore gulch during last storm series. Most slides were on east and southerly terrain near and above treeline. Several slopes cracked and failed on east facing terrain below treeline, but did not slide. 4 slides on south and easterly terrain on south side of Commodore ridgeline. (One slide on an E asp blw tl may have run sympathetic to mitigation on 1.16.16) Biggest one was SS-N -R4D2.5-O/G ,SE above tl