Dense Fog — Animas River Basin, Colorado

2025-12-26 · Animas River Basin, Colorado

Event narrative

Localized dense fog developed within the Animas River Basin on the morning of December 26. The KDRO ASOS at the Durango-La Plata County Airport reported multiple prolonged periods of reduced visibility throughout the night due to mist and fog, though dense fog with visibility of 1/4 mile only briefly developed, lasting less than 30 minutes. No reports of injuries, damages, or fatalities were received.

Wider weather episode

Southwest flow across the southwestern CONUS transported Pacific moisture into southwestern Colorado on December 25. Rain showers fell over much of the San Juans and nearby river basins as a result. Overnight into December 26, pockets of drier mid-level air developed over the same areas which had received rainfall. Clearer skies developed as dense cloud cover moved to the northwest and southeast of the San Juans. Favorable radiational cooling paired with the remaining surface moisture supported the development of dense fog in many of the valleys of southwestern Colorado.

Source: NOAA Storm Events Database, event_id 1302448. Narrative written by the NWS forecast office that issued the report.