Two children are among six people killed in a collision in Montana after a dust storm on Friday night caused a power outage on Interstate 90, a major route in both Montana and the western US.
Montana Highway Patrol Sgt. Jay Nelson said researchers have so far found no other factors that contributed to the pileup that also sent eight other injured people to hospitals.
“Everything points to an isolated extreme weather event,” Nelson said of the investigation, calling the crash one of the worst he had seen in 24 years at the state. “What could people do? It was really panic.”
The compound was just west of Hardin, with additional Billings ambulances to assist. The identities of the dead and the condition of the survivors have not yet been released.
The crash was reported at around 4.30pm, when 21 vehicles, including six commercial semi-trucks, lost control in the dust storm fueled by 60 mph (97 kph) gusts, authorities said.
Nelson said there was no visibility for a mile-long stretch during peak summer hours for people commuting home from work or traveling for outdoor recreation.
It took more than six hours for the road to be fully reopened.
“We had a lot of rubble and complete chaos,” Nelson said.
Gov. Greg Gianforte said on Twitter:“I am deeply saddened by the news of a mass casualty crash near Hardin. Please join me in prayer to lift the victims and their loved ones. We are grateful to our first responders for their service.”
Montana Attorney General Austin Knudsen said in a statement that the Montana Highway Patrol, which he oversees, was investigating. “We will release more information as it becomes available and appropriate out of respect for the lives lost and their loved ones.
A video from The Billings Gazette showed hundreds of tractor-trailers, RVs and cars miles back along the two eastbound lanes of the highway.
Before the buildup, storms popped up in central southern Montana between 1 and 2 p.m. and started moving slowly eastward, said Nick Vertz, a National Weather Service meteorologist in Billings.
Those storms created a severe thunderstorm that covered Hardin and other parts of Montana from mid-afternoon to 9 p.m. Friday. Meteorologists predicted the potential for isolated hail the size of a quarter, scattered wind gusts up to 75 mph (121 kph) and frequent lightning.
A so-called outflow — or a gust of wind produced by storms — flew out about 30 miles (48 kilometers) ahead of the storms, Vertz said.
Winds picked up rapidly around the time of the crash, according to measurements at nearby Big Horn County Airport. About 15 minutes before the crash was reported, a 40 mph (64 kph) gust was recorded and in less than an hour another gust hit 64 (103 kph).
The wind easily picked up dust — a product of recent temperatures into the 1990s and triple digits last week — and reduced visibility to less than 1/4 mile (0.4 kilometers).
“If they looked at the sky while they were in Hardin, they probably didn’t see much of what you’d expect from a thundercloud, maybe not much,” Vertz said. “It was just a wave of wind that appeared out of nowhere.”