Dense Fog in San Juan River Basin, Colorado

Localized dense fog developed within the San Juan River Basin in the early morning of November 22. The KPSO AWOS at the Stevens-Pagosa Springs Airfield reported two brief periods of 1/4-mile visibility overnight due to freezing fog, once near 0100 MST, and again between 0200-0400 MST. No reports of injuries, damages, or fatalities were received.

With a low passing to our south, calm winds and clearing skies began to dominate the region. Though the mid-level atmosphere was quickly drying out, low-level moisture persisted in lower valleys across the western slope of the Rockies. Patchy fog was able to develop across portions of northwestern Colorado as a result, and widespread fog developed over portions of southwestern Colorado before quickly burning up after sunrise.