Tornadoes ripped through five US states overnight, leaving more than 70 people dead Saturday in Kentucky and causing multiple fatalities at an Amazon warehouse in Illinois that suffered "catastrophic damage" with around 100 people trapped inside.
The western Kentucky town of Mayfield was "ground zero" of the storm—a scene of "massive devastation," one official said.
Entire city blocks there were flattened, with houses and buildings ripped apart, and twisted metal, shattered tree limbs and bricks scattered across streets, according to pictures and videos shared on social media.'
"We were pretty sure that we would lose over 50 Kentuckians. I'm now certain that that number is north of 70. It may in fact end up exceeding 100 before the day is done," Governor Andy Beshear told a midday press conference in Mayfield.
The roof of a candle factory collapsed in Mayfield, resulting in "mass casualties" there, Beshear said earlier.
At least one person died when a tornado "pretty much destroyed" a nursing home in the Arkansas town of Monette, a county official said. Another person died elsewhere in the state, local media reported.
Towns in Missouri and Tennessee were affected as well by some of the most powerful tornadoes to hammer the area in years.
President Joe Biden tweeted that the massive storms had inflicted an "unimaginable tragedy" on the area and vowed to provide all needed federal aid.
Lori Wooton was at her daughter's home in the Kentucky town of Dawson Springs — about 70 miles northwest of Mayfield — when, she said, the storm came on with stunning swiftness.
"At first, you know, we were just hearing the rain," she told CNN, "and all of a sudden, it was just very loud like a train.
"It didn't seem like it lasted that long… three or four seconds and it was gone. But then when we got out and started looking at the damage, it was just unbelievable."
One tornado, which first touched down in Missouri, smashed along the ground for over 200 miles in Kentucky, Governor Beshear said.
The longest a US tornado has ever tracked along the ground was a 219-mile storm in Missouri in 1925. Powerful and devastating — as such long-track storms tend to be — it claimed 695 lives.
Images of the latest tornadoes from US news channels showed dark black cylinders sweeping across the ground, illuminated by intermittent flashes of lightning.
At least four Kentucky counties were left devastated.
"Mayfield in Graves County will be ground zero," Kentucky emergency management director Michael Dossett told CNN early Saturday. "The city took… the hardest hit. There is massive devastation," he said.
The governor declared a state of emergency before midnight and said scores of search and rescue officials had been deployed.
Around 200,000 homes in Kentucky and Tennessee were left without power, according to PowerOutage.com.
On the same night a storm ripped through a massive Amazon warehouse in the state of Illinois where around 100 workers were trapped inside, local media reported.
Hundreds of officials were working through the early hours of Saturday to rescue employees at the warehouse — a third of which was reduced to rubble — who were on the night shift processing orders ahead of the Christmas holidays.
Footage shared across US news channels and social media of the Amazon warehouse showed a large part of the facility's roof ripped off, while one of the walls had collapsed into the building.
Illinois Governor J.B. Pritzker said police and state emergency agencies were "coordinating closely with local officials and I will continue to monitor the situation."
In a statement, Amazon spokesperson Richard Rocha said "the safety and well-being of our employees and partners is our top priority right now. We're assessing the situation and will share additional information when it's available."
In Arkansas, some 20 people were trapped after a tornado struck the Monette Manor nursing home, US media reported.
Craighead county official Marvin Day told local news channels that rescuers had successfully pulled out those trapped in the building and the structure was "pretty much destroyed."
Scientists have warned that climate change is making storms more powerful and increasing their frequency, posing a growing threat to areas where extreme weather events are already common.