Dense Fog — Animas River Basin, Colorado

2025-11-24 · Animas River Basin, Colorado

Event narrative

Widespread dense fog developed within the Animas River Basin near and just after sunrise on November 24. The KDRO ASOS at the Durango-La Plata County Airport reported multiple hours of 1/4-mile visibility due to freezing fog, and multiple periods up to 30 minutes long of visibility reduced to less that 1/4 mile. No reports of injuries, damages, or fatalities were received.

Wider weather episode

A shortwave trough brought rain and snowfall to the San Juan mountains on November 23. Overnight, the trough moved out of the region. A weak pressure gradient made for calmer winds, and a drying mid-level atmosphere cleared skies. With the recent precipitation though, low-level moisture remained pooled over southwestern Colorado leading to the development of widespread dense fog.

Source: NOAA Storm Events Database, event_id 1300441. Narrative written by the NWS forecast office that issued the report.