Dense Fog in Grand Flat and Arches, Utah

Widespread dense fog developed within the Utah Grand Flat on the morning of January 3. The KCNY ASOS at the Canyonlands Regional Airport reported a brief period of 1/4-mile visibility from freezing fog shortly before sunrise. Reduced visibility due to mist and fog remained before a prolonged period of less than 1/4 mile visibility due to dense fog developed a couple hours after sunrise and lasted about three hours. No reports of injuries, damages, or fatalities were received.

Potent surface moisture lingered within Utah valleys on the morning of January 3 resulting from widespread rain and snow over the prior two days. A deep upper-level ridge moving overhead made way for clear skies though. With the resulting radiational cooling, morning and early afternoon surface conditions became saturated and supported widespread dense fog development.