Southern San Juan

Avalanche

Chris Bilbrey · Feb 8, 2024 · Southern San Juan

Weather

Obscured skies in the morning with on and off snowfall ranging S1 to S5. Heavier bouts of snow only lasted 20 to 30 minutes. Winds were generally light with brief stints of moderate gusts.

Snowpack

We found 35 to 45 cm of new snow below 10,000 feet. Above that, new snow depths increased to 55 to 60 cm. The warm start, cold finish to this stormy period built a mostly right-side-up storm slab. We did observe a mixture of propagating and non-propagating results in ECTs down about 30 cm at a storm density change (F to 4F transition). These occurred in our northeast snowpit (20 degree aspect) at 10,700 feet. Compression tests (CT) also produced progressive collapse failures at various storm layer depths with easy to moderate force. The new/ old interface, consisting of near-surface facets, was stubborn producing ECTNs and resistant planar CTs. Weaker snow layers below the new snow (around 85 to 90 cm deep) took hard force loading steps to fail at the lower-below treeline elevations where we traveled. The 1/4 interface in our northeast pit was 105 cm deep, 1F- hard (mixture of angular and rounding grains) and no failures observed in snowpack tests (ECTX).

Avalanche

No visibility into upper elevations. None spotted between 8,700 feet and 10,800 feet along creeks or steeper slopes.