'Superfog' leaves at least seven dead and dozens injured after 158-car pile-up

At least seven people are dead after a "super fog" caused a massive 158-car pile-up near New Orleans.

A mixture of dense morning fog and smoke from multiple marsh fires came together to reduce visibility on Interstate 55, leaving behind a long stretch of mangled and burnt-out cars, trucks and tractor-trailers.

Some 25 people have been reported injured, with Louisiana State Police warning that the death toll could continue to climb.

People could be seen climbing out of their vehicles and standing either on the roof of their cars or the side of the road as emergency first responders arrived.

Some vehicles were crushed, while others piled atop one another and were consumed by flames.

Clarencia Patterson Reed was driving with her wife and niece and could see people waving their hands for her to stop.

When she did, her car was hit from behind and on the side by two other vehicles, she told the The Times-Picayune/The New Orleans Advocate.

“It was ‘Boom, boom’ - All you kept hearing was crashing,” she said.

Ms Reed said she was able to escape out of her car, but her wife was pinned inside and suffered injuries to her leg and side.

Another driver, Christopher Coll, said he was already braking when a pickup truck "drove up on top of my work trailer and took me for a ride”.

Mr Coll said he could smell smoke as he heard the sounds of crashing cars and popping tires.

He was able to kick open his passenger door to escape and then helped others - pulling out one person through a car window.

While 25 people were transported to the hospital, with injuries ranging from minor to critical, others sought medical aid on their own, authorities said.

Governor John Bel Edwards asked for prayers “for those hurt and killed" on Monday and issued a call for blood donors to replenish dwindling supplies.

Louisiana State Police shared aerial photos on their Facebook page showing the crashed cars and extensive debris on both northbound and southbound lanes of the elevated interstate, which passes over swamp and open water between lakes Pontchartrain and Maurepas.

State troopers are still working “to notify families, investigate the exact causes of the crashes" and coordinate with the state's transportation department to have the bridge inspected.

School buses were brought in to transport stranded motorists from the accident sites.

State police told reporters at the scene that one vehicle had gone over the highway guardrail and into the water, but the driver escaped unharmed.

The National Weather Service said there were multiple wetland fires in the region. Smoke from the fires mixed with fog to create a “superfog.”

Visibility improved as the fog lifted, according to the agency, but similarly dangerous conditions could occur in coming days.

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