When a good air mass goes bad

Photo credit: Jim Steenburgh, Dept. of Atmospheric Sciences

While the East freezes, the West struggles through stagnant cold.

On Wednesday morning, Jan. 23, it was a smoggy 4°F (–15ºC) at the Salt Lake City airport—but if you were to ascend about half a mile that morning, or head over to the Sundance Film Festival in Park City, you’d have found sparkling sunshine and temperatures around 45°F (7°C).

In a well-mixed atmosphere, temperature drops consistently with height, and pollutants near the surface are dispersed by rising plumes of warm air. When a shallow, stable inversion is present, polluted air is trapped below the inversion.

It’s been dubbed “the mother of all inversions” by Jim Steenburgh, a University of Utah professor and an expert on Western meteorology. Steenburgh runs the Wasatch Weather Weenies blog, where he’s been dolefully documenting the unrelenting cold as well as the buildup of dangerous air pollution near the ground.

The grim reportage is leavened by plenty of cool science and touches of humor. (One entry, which shows the smoggy inversion as viewed from above, is titled, simply, “Ick.”)

—From an article in Atmos News, from the National Center for Atmospheric Research in Boulder, Colorado. Read the entire article here.