About Inversions

Area residents are accustomed to seeing one or two periods of inversion during the winter months. Blame it on our geography, our weather, and that fact that people live here.

Photo Credit: Tom Smart, Deseret Morning News

This valley is surrounded on all sides by mountains. The right meteorological condition - cold temperatures, no breezes - cause the cold air to become trapped. Because the air isn't moving, the pollution also has no where to go and it begins to build up. It is held in place beneath a layer of warm air.

The condition is called an inversion because it is the reverse of a normal air pattern (i.e. - cooler air above, warmer air below).

An inversion will linger until wind or a storm front comes through. The "typical" period is from a few days to a week, although there have occasionally been inversions which have lasted two to three weeks.