Violent spring storms are sweeping across the southern United States. At least four tornadoes were reported in Oklahoma overnight and two others in Arkansas and Kansas.

The massive storm system has already threatened nearly 9 million people across the South. Heavy rain and flash flooding is forecast to fall over the Southeast through Friday.

The tornadoes that ripped across northeastern Oklahoma Wednesday evening injured about seven people. In the city of Tulsa, violent winds pounded suburban neighborhoods, leveling houses and uprooting trees, reports CBS News correspondent Manuel Bojorquez.

An adult and three children were in a pickup truck when a tree crashed on top of it. The family was hospitalized with no major injuries. Tornado sirens rang out.

DD Gillespie said he had just two minutes to get to safety before one of the tornadoes hit.

"I see a funnel cloud - debris just going around in circles. All the high winds came through and just tore up everything, broke out windows," Gillespie said. "It was pretty intense."

Trees snapped power lines; as many as 5,800 homes and businesses lost power.

First responders have been searching homes through the night looking for survivors.

So far, there are no reports of missing people. Four Tulsa schools have canceled classes Thursday.

The National Weather Service will likely determine the intensity of the tornadoes by assessing the damage on the ground.

Meanwhile, other parts of the South are also recovering from strong storms that stretched from Texas to Missouri.

Two flight attendants were hospitalized overnight when their flight was rocked by strong storms, causing an emergency landing.

American Eagle flight 3358 took off from Dallas Fort-Worth International Airport Wednesday morning but was forced to emergency land in Little Rock, Arkansas around noon central time.

"There was actually two of them that got hurt fairly. They were bleeding. Shortly after that quick drop, the pilot got on and said we had to make an emergency landing," a passenger said.

In Memphis, Tennessee, torrential rain soaked the city known for the blues overnight, dropping more than an inch of rain in six hours, reports CBS News correspondent David Begnaud.

To the southwest in Little Rock, Arkansas, a record 4.9 inches of rain fell under 24 hours, sending rushing floodwaters over clogged roads, hampering drivers and creating dangerous conditions.

Rescue crews dragged three people out of the engorged Rock Creek in the heart of Little Rock. They held onto a tree for safety after their car was swept away in the storm.

High water rushed through alley ways, sending heavy objects adrift.

A hail storm rocked Kansas, crisscrossing the entire state. The barrage of ice, rain and wind sent people outside and drivers scrambling.

In Cassoday, Kansas, the wind whipped the rain into near-whiteout conditions, while in El Dorado, hail the size of tennis balls smashed windows and pierced walls of houses. One family's home was severely damaged.

"It went from sounding like quarters on the roof to about golf ball-sized hail. It sounded like basically there was a hurricane outside the front door," said one resident, Joseph Hamilton.