What is super fog? The mix of smoke and dense fog caused a deadly pileup in Louisiana

In this aerial photo, responders are seen near wreckage in the aftermath of a multi-vehicle pileup on I-55 in Manchac, La., Monday, Oct. 23, 2023. A “superfog” of smoke from south Louisiana marsh fires and dense morning fog caused multiple traffic crashes involving scores of cars. (AP Photo/Gerald Herbert)

The National Weather Service called it “super fog” — a combination of thick smoke from fires in marshy wetlands of south Louisiana and the fog that often hangs thick in the air on cool, windless mornings. It was a deadly combination this week. Smoke spreading through the region from a marsh fire east of New Orleans combined with thick fog and reduced visibility on highways to near nothing.