Dust storm causes a 21-vehicle pileup in Montana, killing six

A dust storm caused a 21-vehicle pileup on Interstate 90 in Big Horn County, Montana, on Friday evening, resulting in six fatalities, according to the Montana Highway Patrol.A dust storm caused a 21-vehicle pileup on Interstate 90 in Big Horn County, Montana, on Friday evening, resulting in six fatalities, according to the Montana Highway Patrol.