A tractor-trailer plowed into 11 cars stopped on an interstate highway in coastal Mississippi early Saturday, killing a father and daughter and two young men in a horrendous crash that also closed the highway for more than six hours.

Four people received injuries, none life-threatening, said Lt. Johnny Poulos of the Mississippi Highway Patrol.

The crash started when a pickup truck and the trailer it was hauling overturned, spilling used computer equipment across eastbound Interstate 10, about 10 miles from the Louisiana state line, Poulos said.

"That 18-wheeler continued eastbound through the stopped traffic," Poulos said. "Colliding with all of the vehicles."

Four big rigs and six passenger cars were involved, some too badly damaged to immediately determine their make and model, said Poulos (POH-lus).

The crash scene was "pretty overwhelming," said Poulos, a 16-year veteran.

He said Hancock County Coroner Jim Faulk identified those killed as Randall Mark Wager, 49, and his daughter, 18-year-old Ariana Mary Wager, of Lucedale, Mississippi; and two Louisiana men -- Brandon Alexander Estes, 23, of Slidell, and Ryan Deforest, 21, of Lacombe.

Traffic tie-ups extended into Louisiana after police began detouring eastbound traffic at an exit 2 miles from the state line, Poulos said.