Southern San Juan

Avalanche

Chris Bilbrey · Jan 22, 2020 · Southern San Juan

Weather

We found ourselves in a sunny doughnut hole with a mixture of broken skies to only a few clouds. It looked stormy to the north but moderate winds were the only dynamic weather event observed. Northwest winds produced snow plumes and swirling winds but drifting that we observed was generally light. No slab formation where we traveled.

Snowpack

We traveled on slopes facing north through east to southeast and snow depths ranged from 125 to 150 cm with isolated areas closer to 175 cm deep. Incremental loading has kept persistent weak layers on southeast-facing slopes reactive in Extended Column Test (ECTP 6 & 9) failing in near-surface facets that most likely formed in early January. That same weak layer in east and northeast snowpits did not produce propagating test results and showed signs of rounding - sintering more pronounced on northeast vs east. Northerly aspects with a slightly stiffer upper slab also produced non-propagating ECTs but did so with easier force. Moderate northwest winds were blowing and transporting storm snow, but did not appear to be building fresh wind-slabs. Lots of alpine slopes remained either scoured or stiffened - alpine areas are where the largest variability exists in snow depth and general structure.

Avalanche

None observed