Dense Fog in Animas River Basin, Colorado

Around 3AM, the KDRO ASOS at Durang-La Plata County Airport began reporting visibilities less than 1/4 mile. Satellite imagery also provided an indication of the extent of the fog. As the sun rose, airfield cameras provided by the Federal Aviation Administration and road cameras provided by the Colorado Department of Transportation allowed for visual confirmation of the extent of the dense fog throughout the Animas River Basin. It also allowed for forecasters to judge when to drop the Dense Fog Advisory as cameras indicated improving conditions. 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.