The winds peeled away roofs — leaving homes looking like giant dollhouses — knocked houses off their foundations, toppled trees, brought down power lines and churned up so much debris that it was visible on radar. Highway crews had to use snowplows to clear an Ohio interstate.
Some of the heaviest damage was reported just outside Dayton, Ohio.
"I just got down on all fours and covered my head with my hands," said Francis Dutmers, who with his wife headed for the basement of their home in Vandalia, about 10 miles (16 kilometers) outside Dayton, when the storm hit with a "very loud roar" Monday night. The winds blew out windows around his house, filled rooms with debris and took down most of his trees.
In Celina, Ohio, 82-year-old Melvin Dale Hanna was killed when a parked car was blown into his house, Mayor Jeffrey Hazel said Tuesday.
"There's areas that truly look like a war zone," he said.
Of the injured, more than two dozen were admitted to hospitals.
Ohio Gov. Mike DeWine declared a state of emergency in three hard-hit counties, allowing the state to suspend normal purchasing procedures and quickly provide supplies like water and generators.
Reports posted online by the National Weather Service's Storm Prediction Center showed that 14 suspected tornadoes touched down in Indiana, 12 in Colorado and nine in Ohio. Seven were reported in Iowa, five in Nebraska, four in Illinois and three in Minnesota, with one in Idaho.
Monday marked the record-tying 11th straight day with at least eight tornadoes in the U.S., said Patrick Marsh, a Storm Prediction Center meteorologist. The last such stretch was in 1980.
"We're getting big counts on a lot of these days, and that is certainly unusual," Marsh said.
To the west, thunderstorms dropped hail as large as tennis balls in Colorado, and dozens of drivers in Nebraska pulled off Interstate 80 with broken windshields.
Forecasters warned of the possibility of powerful thunderstorms during the Tuesday afternoon rush hour in the Kansas City area, as well as more bad weather in Ohio.
A tornado with winds up to 140 mph (225 kph) struck near Trotwood, Ohio, a community of about 24,500 people 8 miles (12 kilometers) outside Dayton. Several apartment buildings were damaged or destroyed, including one complex where the entire roof was torn away, and at least three dozen people were treated for cuts, bumps and bruises.
"If I didn't move quick enough, what could have happened?" said Erica Bohannon of Trotwood, who hid in a closet with her son and their dog. She emerged to find herself looking at the sky. The roof was gone.
Just before midnight, about 40 minutes after that tornado cut through, the National Weather Service tweeted that another one was crossing its path.
Only a few minor injuries were reported in Dayton. Fire Chief Jeffrey Payne called that "pretty miraculous," attributing it to people heeding early warnings. Sirens went off ahead of the storm.
Some of the people treated at the area's Kettering Health Network hospitals were hurt during storm clean-up itself, while others may have waited before seeking treatment from storm injuries, said spokeswoman Elizabeth Long.
A boil-water advisory was issued after the city's pumping stations lost power. Dayton Power & Light said more than 50,000 customers remained without electricity and restoration efforts could take days.
A high school gym in Dayton was designated an emergency shelter until authorities realized it was unusable. Vandalia's school system tweeted that it is ending the year two days early because of building damage. In nearby hard-hit Brookville, where the storm tore off the school's roof, classes were canceled.
In Indiana, a twister touched down Monday evening in Pendleton, about 35 miles (56 kilometers) from Indianapolis. At least 75 homes were damaged there and in nearby Huntsville, said Madison County Emergency Management spokesman Todd Harmeson. No serious injuries were reported.
Pendleton residents were urged to stay in their homes Tuesday morning because of downed power lines and other dangers.
"People are getting antsy. I know they want to get outdoors, and I know they want to see what's going on in the neighborhood," Harmeson said. But he added: "We still have hazards out there."
Outbreaks of 50 or more tornadoes are not uncommon, having happened 63 times in U.S. history, with three instances of more than 100 twisters, Marsh said. But Monday's swarm was unusual because it happened over a particularly wide geographic area and came amid an especially active stretch, he said.
As for why it's happening, Marsh said high pressure over the Southeast and an unusually cold trough over the Rockies are forcing warm, moist air into the central U.S., triggering repeated severe thunderstorms and tornadoes. And neither system is showing signs of moving, he said.
Scientists say climate change is responsible for more intense and more frequent extreme weather such as storms, droughts, floods and fires, but without extensive study they cannot directly link a single weather event to the changing climate.
Associated Press writers Dan Sewell and Amanda Seitz in Cincinnati; David Runk in Detroit; Kantele Franko and Andrew Welsh-Huggins in Columbus, Ohio; Rick Callahan in Indianapolis; John Hanna in Topeka, Kansas; and Marjory Beck in Omaha, Nebraska, contributed.
This story has been corrected to show that the age of the man who was killed was 82, not 81. It also corrects the spelling of his last name to Hanna, not Hannah.