Dense Fog — Northwestern San Juan Mountains, Colorado

2025-11-23 to 2025-11-24 · Northwestern San Juan Mountains, Colorado

Event narrative

Areas of dense fog developed within the upper valleys of the San Juan mountains overnight from November 23 to 24. The KTEX AWOS at the Telluride Regional Airport reported three periods of 1/4-mile visibility due to dense freezing fog throughout the night, each lasting less than two hours. 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 1300437. Narrative written by the NWS forecast office that issued the report.