A deadly multi-car pileup occurred on Interstate 55 in Louisiana, near New Orleans, due to a phenomenon called "super fog," according to police. The crash involved at least 158 vehicles and resulted in seven fatalities and over 25 injuries of varying degrees. The stretch of Interstate 55 over Lake Pontchartrain is expected to remain closed for an extended period, along with Interstate 10 and Interstate 310.

Super fog is formed when smoke from nearby marsh fires combines with dense fog to create extremely low visibility conditions. These conditions make driving hazardous, with visibility dropping to near-zero in some spots. The National Weather Service explained that super fog occurs when condensed water vapor mixes with smoke and moisture released from smoldering organic material.

Emergency crews have been working to clear the crash scene and debris from both northbound and southbound lanes. A portion of the crash scene caught fire after the initial incident. The cause of the multi-car pileup has been attributed to the super fog, which severely compromised visibility on the highway.

Drivers have been advised to use their headlights on low beams when driving in foggy conditions and to reduce speed. The presence of super fog makes it particularly dangerous for cars traveling at high speeds. In areas experiencing dense fog, it is recommended to delay travel plans or find alternate routes with less dense fog.