Dense Fog — Upper Gunnison River Valley, Colorado

2025-12-11 · Upper Gunnison River Valley, Colorado

Event narrative

Localized dense fog developed within the Upper Gunnison River Valley on the morning of December 11. The KGUC AWOS at the Gunnison'Crested Butte Regional Airport reported multiple periods of reduced visibility due to fog. For roughly two hours beginning near sunset, 1/4-mile visibility was reported. No reports of injuries, damages, or fatalities were received.

Wider weather episode

Northwesterly flow brought enhanced moisture and light snow showers to northwestern Colorado on December 10. Overnight into December 11, high pressure moved overhead, leaving clearer skies and cooling temperatures. High cloud cover mildly hampered radiational cooling, keeping dense fog duration predominantly short-lived over high-elevation valleys where surface moisture lingered.

Source: NOAA Storm Events Database, event_id 1302445. Narrative written by the NWS forecast office that issued the report.