ATLANTA (AP) — Tropical Depression Claudette claimed 12 lives in Alabama as the storm swept across the south-eastern US, causing flash flooding and spurring tornadoes that destroyed dozens of homes.

Ten people, including nine children, were killed Saturday in a fiery, multi-vehicle crash about 35 miles (55 kilometres) south of Montgomery on Interstate 65, according to Butler County coroner Wayne Garlock.

He said the vehicles likely hydroplaned on wet roads, with eight children, ages 4 to 17, killed in a van belonging to a youth ranch for abused or neglected children operated by the Alabama Sheriffs Association. Two people died in separate vehicles, Garlock told local news outlets — 29-year-old Cody Fox and his nine-month-old daughter, Ariana, both of Marion County, Tennessee.

“He was a great guy and we’re really gonna miss him,” said Aaron Sanders, who worked with Fox at the emergency management agency in Marion County. He said Fox also ran a hot tub business with his father and doted on his daughter. “He just loved her to death, and that was his life.”

Multiple people were also injured.

The National Transportation Safety Board tweeted that it was sending 10 investigators to the area Sunday to investigate the crash, which photos showed included at least four burned vehicles, including two large trucks. It said the inquiry would focus on vehicle technologies such as forward collision warning systems, fuel tank integrity and occupant survivability.

Meanwhile, a 24-year-old man and a three-year-old boy were killed when a tree fell on their house just outside the Tuscaloosa city limits Saturday, said Captain Jack Kennedy of the Tuscaloosa Violent Crimes Unit.

The deaths occurred as drenching rain pelted northern Alabama and Georgia late Saturday. As much as 12 inches (30 centimetres) of rain was reported earlier from Claudette along the Mississippi Gulf Coast.

Flash flood watches were posted Sunday for northern Georgia, most of South Carolina, the North Carolina coast, parts of south-east Alabama and the Florida Panhandle. A tropical storm warning was in effect in North Carolina from the Little River Inlet to the town of Duck on the Outer Banks. A tropical storm watch was issued from South Santee River, South Carolina, to the Little River Inlet, forecasters said.

WBRC-TV reported that search efforts were also under way for a man believed to have fallen into the water during flash flooding in Birmingham. Crews were using boats to search Pebble Creek.

The eight children killed in the van were returning to a youth ranch near Camp Hill, north-east of Montgomery, from a week at the beach in Gulf Shores, youth ranches CEO Michael Smith told The Associated Press. The van caught fire after the wreck. Candice Gulley, director of the Tallapoosa County ranch, was pulled from the flames and remained hospitalised in Montgomery in serious but stable condition. “She’s going to survive her physical injuries,” Smith said.

Two of the dead in the van were Gulley’s children, ages 4 and 16. Four others were ranch residents and two were guests, Smith said.

“This is the worst tragedy I’ve been a part of in my life,” said Smith, who drove Sunday to the ranch to talk to the remaining residents who had returned from Gulf Shores in a separate van and did not see the wreck.

“Words cannot explain what I saw,” Smith said of the accident site which he visited Saturday. “We love these girls like they’re our own children.”

Garlock said the location of the wreck is “notorious” for hydroplaning, as the northbound highway curves down a hill to a small creek. Traffic on that stretch of I-65 is usually filled with vacationers driving to and from Gulf of Mexico beaches on summer weekends.

“Butler County has had one of the most terrible traffic accidents,” county Sheriff Danny Bond wrote on Facebook, adding: “I believe this is the worst ever in our county.”

The Tallapoosa County school system said counsellors would be available Sunday at the 225-student Reeltown High School, where some of the ranch residents were students. Smith said the ranch, which is Christian-based, would likely have a memorial service later, asking for prayers as he began to cry.

A GoFundMe account was set up for Tallapoosa County Girls Ranch to help offset the costs of funeral expenses, medical costs for the injured, and counselling for those impacted.

Gulley, the lone survivor from the van, had worked with children for years, beginning when she and her husband were house parents at the ranch for seven years.

“During those years there have been 74 girls that have come through our house and called us mom and dad,” she told the Opelika-Auburn News in August 2019. She said she then became a relief parent, working on fund-raising and being involved in the community, before she became the ranch director.

“My heart goes out to the loved ones of all who perished,” Alabama Govenor Kay Ivey said in a statement.

Top winds from Claudette remained near 30 mph (45 kph) on Sunday. National Hurricane Center forecasters predicted it would strengthen back to tropical storm status Monday over eastern North Carolina before heading out to sea in the Atlantic Ocean.

The centre of Claudette’s disorganised circulation was located about 10 miles (15 kilometres) west-southwest of Athens, Georgia, on Sunday afternoon. It was moving east-northeast at 17 mph (28 kph), the National Hurricane Center said.

Aside from rainy weather, it seemed to be business as usual along North Carolina’s Outer Banks on Sunday.

At Ace Hardware in Avon, shift manager David Swartwood said they were preparing for whatever might come, but the overall sense was that it wouldn’t be that bad. He said winds from the south don’t usually cause huge flooding problems, so “we don’t really anticipate any bad scenarios”.

“Everybody here has been through it many, many times, so we’re used to the drill,” he said. “We’ve been prepared.”

For the hardware store, he said, that means having supplies like flashlights, batteries, tarps, generators, ropes and sandbags on hand. As of Sunday morning there wasn’t a huge rush for those items.

At Stack ’em High in Kill Devil Hills, a restaurant that specialises in pancakes, co-owner Dawn Kiousis said Sunday morning restaurant service was busy.

“We’re serving just like normal,” she said. “As far as I’m aware, it’s not going to be too much of a hazard for us.

“You keep your eye on the weather and you prepare as much stuff in advance as you can,” she said. “Just know she’s gonna win. Mother nature is going to do what she’s going to do, so you just prepare.”