Dozens of people were feared dead, and communities across the Midwest and South were digging through rubble on Saturday after a string of unseasonably powerful storms and tornadoes swept across six states overnight.
Gov. Andy Beshear of Kentucky said that at least 70 had been killed, and the state’s death toll could increase to more than 100. The state was hit by four tornadoes, he said, including one that stayed on the ground for more than 200 miles.
In Mayfield, Ky., about 110 people had huddled inside a candle-making factory when a tornado ripped through it. About 40 people were rescued, but Mr. Beshear said he believed “dozens” had been killed there. At a news briefing on Saturday, shaken local officials said they were struggling to comb through the debris amid blocked roads and lost water and electrical service.
“This has been the most devastating tornado event in our state’s history,” Mr. Beshear said at the briefing. “The level of devastation is unlike anything I have ever seen.”
Other states were also hit hard. Officials said that at least six people had been killed at an Amazon warehouse in Illinois, four had died in Tennessee and two had died in Arkansas.
The storms — dark and immense funnel clouds that roared across the nighttime landscape — obliterated homes, churches and businesses, set buildings on fire and knocked a train with 28 empty rail cars from its tracks, leaving unearthly scenes of destruction.
In Mayfield, among the hardest-hit communities, the center of town had become a perilous maze of downed utility lines, dangling tree limbs and scattered debris. Jesse Perry, the judge executive in Graves County, which includes Mayfield, said local officials were “in the trenches, trying to find people.”
“We need your prayers,” he said, voice wavering at a news conference on Saturday. “We need your help.”
President Biden said that he had approved an emergency declaration for Kentucky, allowing federal resources to flow into the state.
“We’re going to get through this, and we’re going to get through this together,” Mr. Biden said at a news conference. “The federal government is not going to walk away.”
In Arkansas, a 94-year-old died and five people were injured when a tornado demolished the Monette Manor nursing home, said Monette’s mayor, Bob Blankenship.
Mandi Sanders, who works at the home, said staff members helped residents cover their heads with pillows to protect them from flying glass and debris before the walls caved in and parts of the roof collapsed.
“It was like a roaring train,” she said. “I didn’t think it would ever end.”
A person was also killed at a Dollar General store in nearby Leachville, Ark., Gov. Asa Hutchinson said.
“Probably the most remarkable thing is that there’s not a greater loss of life,” Mr. Hutchinson said at a news briefing.
Scientists are not sure whether there is a link between climate change and the frequency or strength of tornadoes, in part because of limited data. But researchers say that in recent years tornadoes seem to be occurring in greater “clusters,” and that a so-called tornado alley in the Great Plains — where most tornadoes occur — appears to be shifting eastward.
At least six states — Arkansas, Illinois, Kentucky, Missouri, Mississippi and Tennessee — were hit by tornadoes on Friday night, according to reports from the National Weather Service.
The tornadoes were part of a weather system that was wreaking havoc in many parts of the country, causing substantial snowfall across parts of the upper Midwest and western Great Lakes, said Bill Bunting, the operations chief at the Storm Prediction Center.
The Edwardsville Police Department in Illinois said early Saturday that the storms had resulted in “catastrophic damage to a significant portion” of an Amazon warehouse. Six people were killed and 45 people were confirmed to have escaped the building, James Whiteford, the fire chief, said at a news conference on Saturday evening.
“Earlier this afternoon, the response portion of this incident came to a close, and we’re now focused solely on recovery,” Chief Whiteford said. The authorities will continue to search for people for the next three days during daylight hours, he said.
Complicating rescue efforts were thousands of power outages across the region. About 77,000 customers in Kentucky and 53,000 customers in Tennessee were without power as of Saturday evening, according to PowerOutage.us.