Dense Fog — San Juan River Basin, Colorado

2026-01-01 to 2026-01-02 · San Juan River Basin, Colorado

Event narrative

Patchy dense fog developed within the San Juan River Basin overnight on January 1 and 2. The KPSO AWOS at the Stevens-Pagosa Springs Airfield reported brief 1/4-mile visibility from dense fog near midnight. No reports of injuries, damages, or fatalities were received.

Wider weather episode

A deep Pacific trough brought moist southwesterly flow to much of the western CONUS on January 1. A weak upper-level jet streak arrived in coincidence with the surge of moisture, prompting widespread precipitation in western Colorado throughout the morning of the 1st. Strong cold air advection behind the storms rapidly saturated valleys, and areas of dense fog developed during throughout the night and into the morning of January 2.

Source: NOAA Storm Events Database, event_id 1309212. Narrative written by the NWS forecast office that issued the report.