This photo shows a thin layer of haze below the level of the ridge tops of the Wasatch Mountains in Utah. It was taken above Park City from an altitude of approximately 8,500 ft (2,590 m) on October 19, 2013. The first substantial snowfall of the season in the Wasatch Range had occurred two days prior to my flight. The snow cover helped to cool the air above, which then settled into the lower valleys to the east of the Wasatch Range. Cooling of the lower atmosphere set up a shallow temperature inversion – warm air above cold. Inversions such as this inhibit circulation in the lower valleys because the cooler, denser air is essentially trapped at the ground. If similar weather conditions persist for several days, which isn’t unusual during October, the buildup of contaminants, and even water vapor, in the trapped, stagnant air results in noticeably hazy skies.
Park City, Utah Coordinates: 40.6594, -111.49
Photographer: Brent Watson --used with permission
