Flash flooding is a big concern following the storms, and flood warnings are in effect Saturday night for a wide stretch of the country. The Weather Channel's Scott Newell reports.

The death toll has jumped to 12 in the aftermath of a swarm of destructive twisters that tore through the Midwest, killing seven adults and two children in Oklahoma and causing three deaths in Missouri blamed on flooding.

Floodwaters also proved deadly in Oklahoma, where a 4-year-old girl died after she was swept away while taking shelter with her family in a ditch, according to police.

It is unclear whether the girl is one of the nine people who died as five tornadoes — one a half-mile wide — struck the Oklahoma City area Friday evening, terrorizing communities already battered by deadly storms this spring.

The Oklahoma Office of the Chief Medical Examiner told NBC News seven adults and two children are confirmed dead, including a mother and her small child.

The medical examiner said that five of the nine dead had been positively identified and called on the public's help to identify the others. "If someone is missing a loved one from last night’s tornado, we would encourage them to contact our office at 405-239-7141," said Amy Elliott, of the medical examiner's office.

Hospitals in Oklahoma City reported 104 injuries, including five critical patients.

At least five people killed were in vehicles and may have been trying to flee as dark clouds gathered and warning sirens wailed, authorities said.

Marcus Jolly, 32, of El Reno told The Oklahoman newspaper the scene along Interstate 40 "was a war zone. There were semis turned over and skeletons of buildings remaining.”

The twisters came just 11 days after a monster tornado left 24 dead in the Oklahoma City suburb of Moore, where power outages were reported Friday.

Mark Wiley, meteorologist at the National Weather Service’s southern region headquarters in Fort Worth, said early Saturday that there had been five confirmed tornadoes in the Oklahoma City area on Friday and one in the Tulsa area early Saturday.

A total of 12 tornadoes hit Missouri and Illinois around St. Louis, where “numerous homes” were damaged. Wiley did not have any information about casualties there. Two twisters touched down briefly in North Dakota, but did not do any damage.

The Oklahoma City area “definitely” experienced the worst of the bad weather, Wiley said, with wind gusts of up to 90 mph, baseball-sized hail and extensive flooding.

Oklahoma resident Garrett Occhipinti speaks with MSNBC via phone about a photo he took of the storm that showed massive wall clouds stretching for over a mile.

“We have several reports of water going into homes and dozens of people having to be rescued on the streets, especially along Interstate 40,” Wiley said. “It was not a good night to be in the Oklahoma City area.”

For Saturday, Wiley said the storm was moving toward Arkansas, Kentucky, Tennessee and East Texas, but did not “look as severe as yesterday.”

The worry now turns to flash flooding. Wiley said about 6 to 8 inches of rain had fallen in 12 hours between 7 p.m. Friday and 7 a.m. CT Saturday. The Weather Channel reported that May 2013 is the wettest May on record in Oklahoma City.

Friday, the terror came from tornadoes boasting baseball-sized hail and winds so strong they tossed tractor-trailers off the interstate. Meteorologists said the storm's fury didn't match that of the tornado that struck Moore on May 20 but dumped around 8 inches of rain on the area.

An SUV used by Weather Channel meteorologist Mike Bettes and a crew of storm trackers was thrown 200 yards by one tornado near Oklahoma City suburb El Reno. The vehicle tumbled about eight times and came to rest in a field, Bettes said. Some members of the crew suffered minor injuries, and the vehicle was destroyed.

"That was the scariest moment of my life," Bettes said. "I saw my life flash before my eyes."

Oklahoma Highway Patrol Trooper Betsy Randolph said the woman and baby were killed when the SUV they were in overturned on Interstate 40 between El Reno and Yukon.

Many of the injured were hurt in accidents along Interstates 35 and 40 west of the city, where at least three semi-trailer rigs were overturned after the biggest tornado touched down near El Reno, authorities said.

Bart Kuester, 50, a truck driver from Wisconsin, said he was driving along Interstate 35 past Moore when he realized a dangerous storm was approaching.

"I heard the sirens going off and I could see it coming," he told The Associated Press. Kuester said the interstate was flooded and jammed with people trying to outrun the storm.

"Everyone was leaving. ... Just because that one that hit Moore was so fresh in their memory," he said.

Authorities said some of the worst damage on Friday was from flooding around El Reno and Yukon and the danger continued into Saturday.

The National Weather Service issued flash flood warnings for parts of Oklahoma early Saturday.

There were also flash flood warnings in place for parts of Iowa, Illinois, Indiana, Missouri, Arkansas and Kansas.

On Friday, one tornado turned south from Oklahoma City and then toward the suburb of Moore, which was hit by a devastating twister on May 20 that killed 24 people and injured hundreds of others.

“I think we are still a little shaken by what happened in Moore. We are still burying children and victims, so our emotions are still strong," Oklahoma City Mayor Mick Cornett told Reuters.

Gov. Mary Fallin declared a state of emergency.

"This has been a very large storm that hit a lot of communities," she told KFOR. She said she had heard from at least 30 fellow governors offering assistance.

At Will Rogers World Airport in Oklahoma City, where winds hit 71 mph, all flights were canceled and about 1,000 travelers were herded underground, where they were told to put their hands on their heads. The airport reopened Saturday morning, but all morning departures were canceled.

Tornado warnings — meaning a funnel cloud that could become a tornado had been spotted in the area — were in effect much of the day for numerous counties in Oklahoma, Missouri, Illinois and Wisconsin.

Forecasters sounded the alarm that much of the Midwest — already pummeled by a week of tornadoes and flooded with drenching rains — was facing another round of violent weather overnight and into the weekend.

Observers at Tinker Air Force Base reported a tornado on the ground near the base southwest of Oklahoma City. In Norman, home to the University of Oklahoma, a tornado touched down near Norman North High School and Norman Regional Hospital.

Buildings at Lambert-St. Louis International Airport were damaged by tornadoes with debris strewn across the runway. The airport was closed because of the damage, but re-opened just before midnight, the airport said in a statement.

Another tornado touched down Friday night 7 miles northeast of Moscow Mills, Mo., about 50 miles northwest of St. Louis. In St. Charles County, 24 houses were severely damaged or destroyed, said Mike O'Connell, communications director for the Missouri Department of Public Safety.

The National Weather Service evacuated its St. Louis office as tornado warnings were issued for north and northeastern St. Louis and surrounding counties.

Janet Shamlian and Aaron Marmelstein of NBC News, Mike Bettes of The Weather Channel, and Reuters contributed to this report. Follow M. Alex Johnson on Twitter and Facebook.

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