Southern San Juan
SnowpackChris Bilbrey · Dec 5, 2019 · Southern San Juan
Weather
Periods of S2 to S5 snowfall during the morning. Winds were light below and near treeline with periods of moderate gusts. Skies broke around Noon and snowfall turned intermittent and showery. Winds in the alpine shifted to a northerly orientation and snow plumes were visible off high peaks. It looked like the west crest of the range took the brunt of winds from our vantage point.
Snowpack
We found 5 inches of new snow in the parking lot and by the time we reached the turnoff to Columbus Basin, snow accumulation increased to 13 inches. We found up to 16 inches near treeline and drifts almost two feet. The storm snow came in right side up with the bottom six inches 4F with F above. We observed numerous loose dry sluffs from steep, rocky terrain during a period of high precipitation rates in the morning. None of the sluffs we saw contributed to slab release and majority were small. The snowpack in this area is the deepest we've found in the La Plata Mountains this season. We did not observe any cracking or collapsing on northerly-facing slopes below and near treeline where we traveled. 3 cm of 1 to 2 mm facets exists at the ground below a stiff slab. This layer was non-reactive in long-column test. We observed a couple non-propagating results within the slab that formed over the last two weeks. We could easily trigger small, harmless soft slab sluffs on slopes around 35 degrees. They did not propagate outward and only ran short distances.