At least 6 killed in massive pileup on Montana freeway amid dust storm

At least six people have died and several more injured after a dust storm fueled by wind gusts topping 60 miles per hour caused a pileup Friday evening on Interstate 90 in Montana, authorities said.

At least 21 vehicles crashed, authorities said. Montana Highway Patrol Sgt. Jay Nelson said weather was likely the cause. 

"It appears as though there was heavy winds, causing a dust storm with zero visibility," he said.