Dense Fog — Animas River Basin, Colorado

2025-04-20 · Animas River Basin, Colorado

Event narrative

According to the KDRO ASOS in Durango, dense fog developed at the airport around 1:15 AM local time, with visibility rapidly dropping to 1/4 mile or less. The KDRO ASOS continued to report this very low visibility through approximately 7:30 AM local time, at which point visibility began to gradually improve. The fog had fully lifted by 9:00AM local time. Satellite imagery also indicated this area of dense fog stretching along the lower elevations of the zone, close to the New Mexico border, and extending into neighboring forecast zones. No reports of injuries, damages, or fatalities were received in association with this event.

Wider weather episode

A wet spring storm had moved through western Colorado in the days before this event, bringing mountain snow, as well as mixed rain and snow in the lower elevation valleys. Particularly, in the southern Colorado valleys, rain and snow allowed for increased surface moisture to become trapped. As skies cleared and temperatures cooled, this trapped moisture condensed, becoming patchy dense fog across the southwestern Colorado valleys.

Source: NOAA Storm Events Database, event_id 1257253. Narrative written by the NWS forecast office that issued the report.