Friday night brought severe weather that turned deadly in parts of the country, including a dust storm that led to a massive pileup on a Montana interstate and rushing floodwaters in Colorado.

A dust storm on Interstate 90 in Montana caused a pileup of 21 vehicles, including six commercial semi-trucks, Friday evening, Montana Highway Patrol Sgt. Jay M. Nelson told USA TODAY. Six people, including two juveniles, died in the crashes, and eight others were hospitalized for their injuries.

Severe flooding Friday night in northern Colorado’s Buckthorn Canyon swept away a home and killed a woman and child inside, authorities said.

Meanwhile, the National Weather Service also issued flood advisories Friday in Arizona’s Yavapai and Coconino Counties as monsoon rain hit the area. Water carried mud to people’s homes in Flagstaff in Coconino County, filling up yards and streets, local news outlets reported.

Weekend forecast: The Plains and the Midwest now face a threat of thunderstorms through the weekend, according to AccuWeather. The storms are expected to target parts of the northern Plains on Saturday before shifting south and east Saturday night.

Deadly Montana pileup blamed on dust storm

There was “zero visibility” during the dust storm on Interstate 90 in Montana, which witnesses said stretched for over a mile long, Nelson said. Video from the scene showed scores of tractor-trailers and cars backed up for miles along two eastbound lanes. It took more than six hours to fully reopen the road, Nelson said.

“This was sort of an unseen extreme weather event that came up,” Nelson said. “In Montana, we don’t usually have dust storms storms to the extent that there’s zero visibility.”

Authorities did not immediately provide additional details on the conditions of the people who were injured.

Nelson said the nearest hospital to the pileup, which took place three miles west of the small southern Montana city of Hardin, was “quickly overwhelmed with the number of injuries.”

“With 24 years on the Montana Highway Patrol, I can’t recall a crash of this significance,” he said. “…Our thoughts and prayers go out to the families of people who tragically lost their lives.”

Traffic is backed up on Interstate 90 after a fatal pileup where at least 20 vehicles crashed near Hardin, Mont., Friday, July 15, 2022.

Gov. Greg Gianforte said he was “deeply saddened” by news of the crash.

Flooding kills 2 in Colorado, authorities say

Severe flooding Friday night in northern Colorado’s Buckthorn Canyon swept away a home and killed a woman and child inside, authorities said.

As officials warned residents to go to higher ground, there were multiple reports of flash flooding near Glen Haven, an unincorporated community in Larimer County, said Larimer County Sheriff’s Office spokesperson David Moore.