Dense Fog in San Juan River Basin, Colorado

Around 3AM local time, the KPSO AWOS at Stephens Field in Pagosa Springs, CO began reporting visibilities less than 1/4 mile. Additionally, satellite imagery provided a gauge for the extent of the dense fog throughout the San Juan River Basin. As the sun rose, road cameras provided by the Colorado Department of Transportation allowed for visual confirmation of the extent of the dense fog. Additionally, the road cameras allowed for forecasters to decide when to drop the Dense Fog Advisories as conditions improved. No reports of injuries, damages, or fatalities were received.

The unsettled pattern that characterized the last week of the month of December brought widespread precipitation to eastern Utah and western Colorado with regularity. This precipitation created pools of rich low level moisture trapped in the lower elevation valleys across the region. As skies cleared and temperatures cooled each night, dense fog then developed in each of these valleys, often widespread. Thanks to the low sun angle, this fog would linger well into the daylight hours before finally lifting.