Six people have died after a dust storm fueled by wind gusts exceeding 60 mph caused a pile-up on Interstate 90 in Montana, authorities said.
Twenty-one vehicles crashed Friday night and Montana Highway Patrol Sgt. Jay Nelson said authorities believe the weather was the cause.
“It looks like there were strong winds, causing a dust storm with zero visibility,” he said.
Although Highway Patrol did not have an immediate count of the number of injured, Nelson said additional ambulances were to be called from Billings to help.
Governor Greg Gianforte said on Twitter: “I am deeply saddened by the news of a mass accident near Hardin. Please join me in prayer in lifting the victims and their loved ones. We are grateful to our first responders for their service.
Montana Attorney General Austin Knudsen, who oversees Highway Patrol, said in a statement, “Montana Highway Patrol is at the scene with other first responders and is investigating the incident. We will post more information as it becomes available and appropriate out of respect for the lives lost and their loved ones.
“My prayers are with everyone affected by the tragic events of the dust storm in Big Horn County today,” Knudsen added.
The incident happened 5 kilometers west of Hardin. Video from The Billings Gazette showed hundreds of tractor-trailers, RVs and cars backed up for miles along the freeway’s two eastbound lanes.
The roots of the dust storm go back several hours, when storms swept through south-central Montana between 1 p.m. and 2 p.m. and slowly began moving east, according to National Weather meteorologist Nick Vertz. Service at Billings.
Those storms sparked a severe thunderstorm watch that covered Hardin and other parts of Montana from mid-afternoon until 9 p.m. Friday. Meteorologists have predicted the potential for isolated quarter-sized hail, scattered wind gusts up to 75 mph (121 km/h) and frequent lightning.
A so-called ‘flow’ – or a surge of wind produced by the storms but able to move faster than them – flew east/southeast about 30 miles (48 kilometers) ahead of the storms, a Vertz said.
A 40 mph (64 kph) wind gust was recorded at nearby Big Horn County Airport at 4:15 p.m. The accident was reported to highway patrol at 4:28 p.m.
When the airport weather station next read at 4.35pm, gusts had reached 62 mph (100 km/h). Another reading 20 minutes later recorded a gust of 64 mph (103 km/h).
The wind easily picked up dust — a product of recent temperatures in the 90s and in the triple digits over the past week — and reduced visibility to less than 1/4 mile (0.4 kilometer).
“If they looked up into the sky while they were in Hardin, they probably didn’t see much of what you’d think for a thundercloud, maybe not even much. at all,” Vertz said. “It was just a wave of wind that kind of appeared out of nowhere.”
As first responders attempt to clear the wreckage, the meteorologist said they can expect to be sheltered from additional winds and thunderstorm activity.
“It should be a relatively clear and calm night for them,” he said.