Catastrophic flooding in Middle Tennessee — the central portion of the US state of Tennessee — left at least 10 people dead and dozens missing on Saturday as record-shattering rainfall washed away homes and rural roads, authorities said.

Business owner Kansas Klein watched in horror from a bridge on Saturday morning as cars and entire houses were swept down a road in Waverly, a town of about 4,500 people that Klein, 48, has called home for more than half his life.

Two girls who were holding on to a puppy and clinging to a wooden board swept past, far too fast for Klein and other onlookers to go down and grab hold of them.

After being told by authorities to go back, Klein returned a couple of hours later, shocked that the floodwaters had almost entirely receded and aghast at the destruction that was left behind.

“It was amazing how quick it came and how quick it left,” Klein said.

Klein said his restaurant, a decade-old New York-style pizzeria, was still standing, but the morning deluge of between 250 to 300 millimetres of rain in Humphreys County had caused floodwaters to reach 2.1 metres inside the eatery, rendering it a total loss.

After leaving his restaurant, Klein walked to the nearby public housing homes and heard yelling. A man had just recovered a baby’s body from one of the homes. Other bodies would soon follow.

“I’m looking at my restaurant, thinking how horrible it was that I lost my restaurant and then I walk around the corner and see someone’s baby dead — my restaurant doesn’t mean a whole lot right now,” Klein told the Associated Press in a phone interview on Saturday night, still in shock as he watched a local news channel air footage he had recorded on his phone hours ago.

The low-income homes — dozens of block buildings known as Brookside — appeared to have borne the brunt of the flash flood, Klein said.

“It was devastating: buildings were knocked down, half of them were destroyed,” Klein said. “People were pulling out bodies of people who had drowned and didn’t make it out.”

Humphreys County Sheriff Chris Davis told news outlets more than 30 people have been reported missing. It was not immediately clear how many had lived at Brookside, located about 96 kilometres west of Nashville.

Two of the bodies recovered were toddlers who had been swept away from their father, Davis told WSMV-TV.

Waverly couple Cindy Dunn, 48, and her husband Jimmy, 49, were rescued from their attic by a crew who used a bulldozer to reach them.

“Hell. That’s what we had to go through,” Cindy Dunn told The Tennessean.

She said her husband woke her up on Saturday, telling her that floodwaters had pushed her car to their backyard. Eventually, the water in their house rose to at least 1.8m high, forcing them to the attic. Dunn said the rooftop wasn’t an option.

“My husband is dealing with cancer. He’s going through chemotherapy. And I am an amputee. So there was no going anywhere besides the attic,” Dunn said.

Dunn said their home and neighbouring houses “are gone”.

Just to the east of Waverly, the town of McEwen was pummeled with about 430mm of rain in less than a day, prompting water rescues, road closures, and communications disruptions. That rainfall total smashed the state’s 24-hour record of 345mm from 1982, according to the National Weather Service Nashville, though Saturday’s numbers remained to be confirmed.

Tennessee Governor Bill Lee tweeted on Saturday, “Tennesseans, please stay cautious of rising floodwaters caused by heavy rainfall in parts of Middle TN (Tennessee). We are actively working with emergency response officials and first responders as they support Tennesseans in flooded areas.”

The Tennessee Emergency Management Agency (TEMA) activated its emergency operations centre and said agencies that include the Tennessee National Guard, the state Highway Patrol, and Fire Mutual Aid were responding to the flooding.

In a bulletin, TEMA called the situation “dangerous and evolving” and urged people to avoid travel in the affected counties.

Klein isn’t sure what the future holds for his family or his town.

He also isn’t sure what happened to the two girls and the puppy he witnessed who had been clinging to the board. He heard that a girl and a puppy had been rescued downstream and that the other girl was also saved, but he wasn’t sure it was them.

“This is the third 100-hundred year flood that we’ve had in about 10 years,” referencing 2010 and 2019 floods. “But this is 100 times worse than either one of them was. [...] The last report I saw was there were 31 missing. This is a small town so the odds are I know most of those people.”