Two semitrailers exploded into flames Wednesday on an interstate in southeastern Wisconsin, killing both drivers and setting other vehicles on fire, authorities said.

Racine County Sheriff Christopher Schmaling said one trailer was southbound on Interstate 94 around 11 a.m. when it hit a construction barrier, overcorrected and crashed onto a median that separated northbound traffic. That caused three northbound cars to crash.

Meanwhile, another semi traveling northbound went into a ditch while trying to avoid hitting the vehicles that had just crashed, Schmaling said. Both trailers burst into flames and set other cars on fire, sending dark plumes of smoke into the sky.

Two people in the cars suffered serious injuries and a third was unharmed, the sheriff said.

The names of those involved were not immediately released, and the accident remained under investigation.

"It only takes one person to make one small error to have devastating effects like we saw today," Schmaling said.

The accident happened near Mount Pleasant, about 24 miles (38 kilometers) south of Milwaukee.

Photos from the scene indicated the semitrailer plummeted off the edge of the interstate onto a road beneath. Near-black smoke washed across the interstate from the still-burning truck.

Authorities closed all lanes of the interstate and transportation officials estimated it would be hours before the scene could be cleared.

A Flight for Life helicopter was called to the scene, but was unable to fly because of adverse weather, Tammy Chatman, a spokeswoman for the service told the Journal Sentinel. There had been scattered rain showers throughout southeastern Wisconsin most of Wednesday morning.

Chatman said Flight for Life sent one of its ground units to help instead.