(CNN)At least three people are dead, including an infant, after a tornado outbreak in Oklahoma overnight, as severe storms threaten more twisters, heavy rain and large hail from Missouri to Texas Sunday.

Multiple large and extremely dangerous tornadoes were reported on the ground simultaneously overnight across parts of Oklahoma, according to the National Weather Service.

Two deaths occurred in Holdenville, and the third near Marietta on I-35, according to Keli Cain, public affairs director for the Oklahoma Department of Emergency Management and Homeland Security.

Oklahoma Governor Kevin Stitt issued an emergency disaster declaration and will be touring storm damage in the Murray County town of Sulphur and Holdenville, he shared in a video message.

There were reports of injuries, property damage, flooding and downed power lines and trees across several counties Saturday night, the Oklahoma Department of Emergency Management said. The extent of the damage was unclear early Sunday.

Sulphur, about 80 miles south of Oklahoma City, saw injuries and impacts from what appears to be at least two large tornadoes overnight as a flood warning was issued for the city, according to the weather service.

“A large and extremely dangerous tornado was located south of Sulphur, moving north at 35 mph. First responders need to prepare for additional tornado impacts immediately!!!” the weather service in Norman warned.

Nearly 47 million people are at risk for severe weather Sunday from east Texas northward into the upper Mississippi River Valley as communities in Nebraska and Iowa survey the destruction the storms have already left behind.

Cities including Dallas and Austin in Texas, Oklahoma City and Tulsa in Oklahoma, Wichita and Topeka in Kansas and the Kansas City metropolitan area could see strong tornadoes as storms push eastward across the southern Plains.

More than 7 million people are under tornado watches early Sunday, stretching more than 800 miles from Texas to southern Wisconsin. The watch areas are due to expire between 3 a.m. and 7 a.m. CT.

The weather service reported two tornadoes crossing Oklahoma’s Highway 9 between Goldsby and Blanchard at the same time late Saturday, as well as a sighting just east of Tinker Air Force Base. And as a tornado headed towards Norman, the University of Oklahoma warned students and staff to “Seek shelter NOW inside the building you are in. Move to lowest floor/interior room.”

Oklahoma’s emergency operations center was activated Saturday, according to a Facebook post from Gov. Kevin Stitt. “Stay weather aware and know where you’ll take shelter if a severe storm threatens your area,” he told residents.

In addition to the tornadoes, storms are bringing heavy rainfall that could exacerbate the life-threatening situation.

Flash flood warnings were in effect in Texas, including in Dallas, Johnson, Parker and Tarrant counties, through Sunday morning, according to the weather service. At least 2-4 inches have already fallen in these areas.

The Storm Prediction Center upped the severe storm threat for Sunday to a level 3 of 5 from eastern Texas to southern Missouri, including Shreveport, Little Rock and Springfield. Communities from southeastern Texas to southern Iowa are under a level 2 of 5 severe storm threat.

Unsettled weather is expected to continue across the midsection of the country into Monday.

“In addition to the severe weather, intense rainfall rates are expected to accompany these thunderstorms at times, leading to a moderate to locally high potential of flash flooding,” the National Weather Service said.

Storms fueled dozens of tornado reports across at least six states Friday and Saturday, with images of flattened homes and debris covering communities seen in communities in Nebraska and Iowa.

A drone view shows emergency personnel working at the site of damaged buildings in the aftermath of a tornado in Omaha, Nebraska, Friday. (Alex Freed, Reuters)

Tornadoes wreak havoc in Nebraska and Iowa

Omaha resident Jason Sunday and his family had just been in their new Elkhorn home 30 days when a tornado hit like a “freight train,” he told CNN affiliate KETV.

As the tornado approached Friday, he sought cover in his home.

“We were in the downstairs bathtub, and it was just like the movie said, it was like a freight train,” Sunday told KETV. “And you knew the roof was coming off because that was a loud pop and sucking motion. It was pretty scary.”

The tornado caused heavy damage to the family’s new home, and now they’re faced with having to rebuild.

“We’re thankful to be alive. We’re very thankful,” Sunday said.

Like Sunday, many residents throughout Omaha and Nebraska are similarly grappling with intense damage to their homes after multiple reported tornadoes touched down Friday.

Elkhorn in Omaha, Nebraska, is one of the hardest-hit communities. Nebraska Gov. Jim Pillen told reporters Saturday it is a miracle there were no deaths.

“Nebraskans are no strangers to severe weather and, as they have countless times before, Nebraskans will help Nebraskans to rebuild,” the governor said in a post on X.

One of the tornadoes to hit Douglas County had a preliminary rating of EF-3 with winds topping 135 mph, according to Chris Franks with the National Weather Service. The other, which hit Omaha’s airport, appeared to be an EF-2, he added.

On the outskirts of Lincoln, Nebraska, a tornado tore the roofs off homes and crossed part of I-80 as it cut through. Multiple cars of a train derailed near Waverly after it was struck by a tornado, according to a railway spokesperson.

Widespread damage was reported after several tornadoes were confirmed Saturday night throughout central Oklahoma. (KOCO via CNN Newsource) Sulphur sees significant damage after tornado outbreak. (KOCO via CNN Newsource)

In Iowa’s Pottawattamie County, roughly 120 homes and businesses were damaged, county emergency management officials said.

A large tornado was reported in the small city of Minden in Pottawattamie County, according to the National Weather Service. Footage obtained by CNN shows the devastation of mangled structures and widespread debris.

There were over 80 tornado reports Friday alone across at least five states, many of which have been confirmed by the weather service or through footage from storm chasers.

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