Six people are dead after a “quick-arising dust storm” blinded drivers on Interstate 90 in Montana. 

The series of crashes happened on July 15th at around 4:50 p.m. on I-90 outside of Hardin, Montana. 

According to The Washington Post, authorities believe that the dust storm brought “heavy winds, causing a dust storm with zero visibility,” said Sgt. Jay Nelson, a spokesman for the Montana Highway Patrol. The pile-up involved at least six tractor trailers. The number of people injured in the wrecks has not been disclosed. 

“We will release more information as it becomes available and is appropriate out of respect of the lives lost and their loved ones,” said Montana Attorney General Austin Knudsen in a statement. “My prayers are with everyone affected by the tragic events during the dust storm in Big Horn County today.”

The crash shut down traffic on eastbound I-90 for hours, while the westbound side was reduced to one lane. 

“If [people] looked up in the sky while they’re in Hardin, they probably didn’t see much of what you’d think of for a thunderstorm cloud, maybe not even much at all,” said Nick Vertz, a Weather Service meteorologist in Billings. “It was just a surge of wind that kind of appeared out of nowhere.”

No further information has been released.