At least six people died in Montana after a windstorm caused 21 vehicles to crash on a highway Friday night, authorities said. The storm’s strong winds and zero visibility are believed to have contributed to the crash, officials said. Montana Gov. Greg Gianforte confirmed the “massive crash” on Twitter, where he encouraged his followers to pray for the victims. First responders work at the scene on Interstate 90 after a deadly pileup where at least 20 vehicles crashed near Hardin, Mont., Friday, July 15, 2022. (Amy Lynn Nelson/The Billings Gazette via AP) “I am deeply saddened by the news of a mass casualty near Hardin. Please join me in prayer to lift up the victims and their loved ones. We are grateful to our first responders for their service,” Gianforte tweeted. STATEN ISLAND ACCIDENT KILLS 3 TEENAGERS, SIX OTHERS INJURED It was not immediately clear how many people were injured in the collision. Montana Highway Patrol Sgt. Jay Nelson said emergency crews responded to the major crash on Interstate 90, which they believed was caused by dust storms and a thunderstorm. “It looks like there were high winds, causing a dust storm with zero visibility,” Nelson said. Traffic is backed up on Interstate 90 after a deadly pileup where at least 20 vehicles crashed near Hardin, Mont., Friday, July 15, 2022. (Amy Lynn Nelson/The Billings Gazette via AP) MA POLICE RELEASE NAMES OF TEENAGERS WHO DIE IN CAR Nick Vertz, a meteorologist with the National Weather Service in Billings, said dust storms first appeared in central southern Montana around 1 to 2 p.m. These dust storms then gave way to a strong thunderstorm that persisted until 9 p.m. of Friday. The crash happened around 4:30 p.m., likely from an “outflow” — a gust of wind that can travel faster than the storm that produces it — that flew ahead of the storms, Vertz said. First responders work at the scene on Interstate 90 after a deadly pileup where at least 20 vehicles crashed near Hardin, Mont., Friday, July 15, 2022. (Amy Lynn Nelson/The Billings Gazette via AP) Videos taken at the scene showed the damaged vehicles causing a backup for miles. NEBRASKA CAR THAT KILLS 2, INJURES 20 POSSIBLY NOT ‘INTENTIONAL’: POLICE First responders remained at the scene overnight to clear the debris. The Associated Press contributed to this report.