At least nine deaths are being reported from severe storms blowing through the South, but the toll could rise.

In Mississippi, officials say up to seven people have been killed. State Director of Health Protection Jim Craig said Monday night that officials are working with coroners to confirm the total.

In north Alabama, Limestone County Emergency Director Rita White said the coroner's office had confirmed two deaths in a twister that caused extensive damage west of the city of Athens.

White says still more victims might be trapped in the wreckage of damaged buildings, but rescuers can't reach some areas because of downed power lines. Separately, Limestone Commissioner Bill Latimer says he has reports from a worker of at least four deaths in the county.

15 dead from Sunday's storms

Earlier, the Arkansas death toll from tornadoes that swept through the Little Rock area on Sunday had been revised downward to 14 from 16, as two victims were counted twice, a governor's aide said today.

Nine of the victims came from the same street in the town of Vilonia — population 4,100 — located just north of the Arkansas capital of Little Rock.

Another person in Oklahoma died in a separate storm, bringing the total to 15. 

The number of people killed in Arkansas, where the storm carved a 129-kilometre path of destruction through suburban Little Rock, may still grow as searchers sift through the rubble, Gov. Mike Beebe said Monday.

"We may have information of more, but we're not in a position to confirm right now," he said at a news conference. "We don't have a count on injured or missing right now."

Tornado risk remains high

Brandon Morris, spokesman for the Arkansas Department of Emergency Management, said crews were working through the rubble Monday in the hope of uncovering survivors and to assess the full extent of the destruction.

"Right now, the main focus is life safety," Morris said. "We're trying to make sure everyone is accounted for."

Among the ruins on Monday was a new $14-million intermediate school in Vilonia that was set to open this fall.

"There's just really nothing there anymore. We're probably going to have to start all over again," Vilonia Schools Superintendent Frank Mitchell said after surveying what was left of the building.

The U.S. National Weather Service warned that the destructive storms — including more tornadoes, damaging winds and very large hail — would continue to strike in parts of Mississippi, Alabama, Tennessee and Louisiana and is expected to last for several days.

The Arkansas tornado was the largest of several produced by a powerful storm system that rumbled through the central and southern U.S. Another twister killed a person in Quapaw, Okla., before crossing into Kansas to the north and destroying 60 to 70 homes and injuring 25 people in the city of Baxter Springs, according to authorities in Kansas.

A death was reported in Baxter Springs, but it wasn't yet known if it was caused by the tornado, making the Oklahoma death the only confirmed death from Sunday's storms outside of Arkansas. A suspected tornado struck near Plain Dealing in northwest Louisiana.

Twister shredded cars, trucks

'We have a storm shelter, thank the Lord.'- Laurie Bogle Jones, Arkansas resident

The Arkansas twister shredded cars, trucks and 18-wheelers stuck along Interstate 40 north of Little Rock. After the storm passed, tractor-trailer rigs tried to navigate through the damage to continue their journeys, while gawkers held smartphones to their windows to offer a grim glimpse of the destruction.

State troopers went vehicle-to-vehicle to check on motorists and found — with genuine surprise — that no one was killed.

"About 30 vehicles — large trucks, sedans, pickup trucks — were going through there when the funnel cloud passed over," said Bill Sadler, a spokesman for the Arkansas State Police.

Laurie Bogle Jones, a resident of Vilonia, Ark., told CBC's Heather Hiscox in a phone interview Monday that she and her family lost half their house when a tornado hit on April 25, 2011. This time, the whole house was destroyed.

"We have a storm shelter, thank the Lord," she said.

Enclosed in that 1.2-metre-by-two-metre space, she said, "it felt as if we were going to be sucked out of there … as though we were going to be sucked up through a straw."

Her kids heard a roar, a "faraway-train type of sound."

Though their house was lost, the family survived. They have no property insurance, however, Jones said.

Karla Ault, a Vilonia High School volleyball coach, said she sheltered in the school gymnasium as the storm approached. After it passed, her husband told her their home had been reduced to the slab on which it had sat.

Relative lull

"I'm just kind of numb. It's just shock that you lost everything. You don't understand everything you have until you realize that all I've got now is just what I have on," Ault said.

U.S. tornado

Motorists check out a tractor-trailer that was blown over by high winds from a severe thunderstorm that passed near Rich Hill, Mo., on Sunday. (Orlin Wagner/Associated Press)

The country had enjoyed a relative lull in violent weather and didn't record the first tornado death until Sunday, when a North Carolina infant who was injured by a twister Friday died at a hospital. But the system that moved through the Plains, Midwest and South on Sunday produced tornadoes that struck several states, including also Missouri, Nebraska and Iowa.

The weather service's North Little Rock office said it was virtually certain that the Mayflower and Vilonia storm would be rated as the nation's strongest twister to date this year.

"It has the potential to be EF3 or greater," said meteorologist Jeff Hood. EF3 storms have winds greater than 219 km/h. "Based on some of the footage we've seen from Mayflower and where it crossed Interstate 40, things were wrecked in a very significant way."

From communities west of Little Rock to others well north of the capital, emergency workers and volunteers went door-to-door checking for victims.

'Gone completely'

"It turned pitch black," said Mark Ausbrooks, who was at his parents' home in Mayflower when the storm arrived. "I ran and got pillows to put over our heads and … all hell broke loose."

"My parents' home, it's gone completely," he said.

Becky Naylor, of Mayflower, said she and her family went to their storm cellar after hearing that tornado debris was falling in nearby Morgan. Naylor, 57, said there were between 20 and 22 people "packed like sardines" in the cellar.

"People were pulling off the highways and were just running in," she said.

Men held the cellar doors shut while the tornado's winds tried to rip them apart.

"It sounded like a constant rolling, roaring sound," she said. "Trees were really bending and the light poles were actually shaking and moving. That's before we shut the door and we've only shut the door to the storm cellar two times."

The other time was in 2011, during an EF-2 tornado that followed nearly the same path.

"This storm was much stronger," Vilonia Mayor James Firestone told ABC's "Good Morning America" early Monday. "The devastation was just tremendous."

Obama vows to help

At a news conference in the Philippines, President Barack Obama sent his condolences and promised the government would help in the recovery.

"Your country will be there to help you recover and rebuild as long as it takes," Obama said.

Storm ratings for Sunday's twisters were not immediately available. Before Sunday, the country had not had a tornado rated EF3 or higher since Nov. 17, a streak of 160 days, the fourth-longest on record. This also would be the latest date for a storm rated EF3 or higher. The previous latest big storm for a year was March 31, 2002.

Sunday was the third anniversary of a 122-tornado day, which struck parts of Mississippi, Alabama, Tennessee, Virginia and Georgia and killed 316 people.

With files from CBC News and Reuters