Northern San Juan
AvalancheChris Dickson · Feb 16, 2025 · Northern San Juan
Snowpack
I measured 90cms (~36") of settled storm snow at 11,700' on a northeast-facing slope in Waterfall Canyon. A friend reported 96cm of unsettled snow towards the end of the storm at 11,000' on a similar aspect. Sunday's warm temperatures and strong morning sun quickly transformed the new snow on east aspects, leading to rapid settlement and heavy moist snow on sunny slopes. A suncrust formed on most slopes facing east through south, but it's possible that afternoon clouds kept west-facing slopes slightly cooler. While no slab character was originally observed in the new snow, Sunday's settlement changed that by midday, and at 1:15pm a backcountry rider reported a large whumph on a previously skied east-facing slope. An ECT performed near treeline, where the 90cm of new snow was measured, at 10am did not result in any failures or propagation (ECTX). The total height of snow in that pit was 240cm.
Avalanche
I drove along Highway 145 on Sunday morning and observed a minimal amount of natural activity, then I toured in Waterfall Canyon and only found one recent natural Storm Slab avalanche below treeline and several slab avalanche that failed during the storm.