Authorities in southern Michigan have searched through rubble and debris in the aftermath of suspected tornadoes that killed four people during powerful storms also blamed for two deaths in Oklahoma.

The Oklahoma State Patrol says it closed a highway south of Sallisaw after a barge struck a bridge over the Arkansas River.

Six teenage girls on a high school lunch break were killed when their small car with only four seats collided with a large truck hauling rocks, the Oklahoma Highway Patrol said Wednesday.

Six Oklahoma high school students who were headed off campus for their lunch break were killed Tuesday after their car collided with a semi-truck, authorities said.