Southern San Juan
AvalancheChris Bilbrey · Mar 18, 2019 · Southern San Juan
Weather
Overcast and cool with off and on snow showers (S-1). Snowfall did not add up to any measurable accumulations. Weather today kept southerly-facing slopes locked up and loose wet avalanche concerns did not develop at all elevations where we traveled.
Snowpack
The snowpack is generally beginning its long transition from winter to spring. Southerly-facing slopes remained frozen from overcast skies while northerly-facing slopes still holding soft surface snow. Easterly-facing slopes had a thin, breakable sun crust that made for challenging riding conditions. Found moist snow from previous day warm temperatures down approx. 10 cm below treeline and approx. 5 cm near and above treeline. Possible wet slab activity from Sunday on south and southwest aspects of Jura Knob. Slides originated from steep, rocky terrain with an overall thin snowpack. Only other recent activity estimated around natural cycle on 3/13. Dug a pit on a southwest aspect at 12,00 feet and found a 1 meter, 1F slab sitting above 60 cm of rounding facets and chains of depth hoar above the ground. ECTs produced non-propagating test results within top meter.
Avalanche
Each individual slide was no larger than a D2, but where debris converged below was large enough to produce minor vegetation damage. Slides ran approx. 1,500 vertical feet into headwaters of Engineer Creek.