(CNN) — A dust storm caused a 21-vehicle collision on Interstate 90 in Big Horn County, Montana, Friday night, killing six people, according to the Montana Highway Patrol.
Montana Attorney General Austin Knudsen said first responders are investigating the crash west of Hardin and more information will be released when it becomes available.
“This investigation is still ongoing. We will release more information as it becomes available and appropriate out of respect for the lives lost and their loved ones,” Knudsen said.
Interstate travel was rerouted overnight, but I-90 has since reopened, the highway patrol said.
“Deeply saddened by the news of a mass casualty crash near Hardin. Please join me in prayer to honor the victims and their loved ones. We are grateful to our first responders for their service,” Governor Greg Gianforte tweeted Friday.
Ariel Dehart witnessed a mobile home break open in the crash while driving west on I-90 near Hardin.
Dehart told CNN that it happened moments after the crash. There were only a few first responders on the scene at the time, he said.
“Visibility was so poor and scary,” Dehart said. “The air was warm and creepy. It was like wearing sepia-tinted glasses. It was so crazy.”
“When I saw the ripped up RV, my stomach crumpled,” he said. “But the owner was frantically putting his throw pillows back in the trailer, and he was very sad because obviously he was very upset by what had just happened.”
José Strickland also witnessed the multiple crash. He told CNN that he skidded to a stop when the crash occurred right in front of him on I-90.
Strickland says he and others helped get an elderly man out of his vehicle, onto a stretcher and into an ambulance.
For about 45 minutes after the accident, Strickland says he stayed behind helping people at the scene.
“Visibility dropped in an instant,” Strickland wrote in a Facebook post about his experience. “I still can’t get over the fact that we were 1 vehicle away from disaster.”
CNN’s Zoe Sottile contributed to this report.