At least four people, including a child, have died as tornadoes swept through Oklahoma over the weekend, authorities said Sunday as emergency crews assessed the extensive damage to homes and businesses from the high winds, hail and flooding.

Severe storms threaten more twisters, heavy rain and large hail from Missouri to Texas, according to the National Weather Service.

Dozens of reported tornadoes have wreaked havoc in the nation’s midsection since Friday, with flood watches and warnings in still in effect Sunday for Oklahoma and other states — including Kansas, Missouri, Arkansas and Texas.

In Oklahoma, a tornado ripped through Holdenville, a town of about 5,000 people, late Saturday, killing two people, and injuring four others, Hughes County Emergency Medical Services said in a statement Sunday. Holdenville is roughly 80 miles from Oklahoma City.

A third death was reported in Marietta on I-35, according to Keli Cain, public affairs director for the Oklahoma Department of Emergency Management and Homeland Security.

A fourth death happened in the hard-hit town of Sulphur in Murray County, Oklahoma, Gov. Kevin Stitt said in an update on Sunday.

“My prayers are with those who lost loved ones as tornadoes ripped through Oklahoma last night,” he said.

The governor issued an executive order Sunday declaring a state of emergency in 12 counties due to the fallout from the severe weather as crews worked to clear debris and assess damage from the severe storms that downed power lines.

“It seems like every business downtown has been destroyed now here in Sulphur,” Gov Stitt said. “It’s definitely the most damage since I’ve been governor that I’ve seen.”

He added that around 30 people were injured in Sulphur and their conditions are unknown.

Nearly 33,000 customers were without power in Oklahoma as of Sunday morning, according to poweroutage.us, which tracks electric utility outages. In Texas, nearly 67,000 customers were without power.

Significant destruction from the storm was reported in the southern Oklahoma community of Sulphur and well as around Marietta, where a hospital was damaged, according to the Oklahoma Office of Emergency Management.

A tornado is seen near north of Waverly, Nebraska on 27 April (Omaha World-Herald)

In Sulphur, where an unidentified person died during a tornado that hit Saturday night (AP)

Residents in other states were also digging out from storm damage.

A tornado in suburban Omaha, Nebraska, demolished homes and businesses Saturday as it moved for miles through farmland and into subdivisions, then slammed an Iowa town.

Fewer than two dozen people were treated at Omaha-area hospitals, said Dr. Lindsay Huse, health director of the city’s Douglas County Health Department.

“Miraculous” she said, stressing that none of the city’s injuries were serious. Neighboring communities reported a handful of injuries each.

Gopala Penmetsa walks past a damaged house after a tornado passed through the area near Omaha, Nebraska on 26 April (Omaha World-Herald)

The tornado damage started Friday afternoon near Lincoln, Nebraska. An industrial building in Lancaster County was hit, causing it to collapse with 70 people inside. Several were trapped, but everyone was evacuated, and the three injuries were not life-threatening, authorities said.

One or possibly two tornadoes then spent around an hour creeping toward Omaha, leaving behind damage consistent with an EF3 twister, with winds of 135 to 165 mph, said Chris Franks, a meteorologist in the National Weather Service’s Omaha office.

Ultimately the twister slammed into the Elkhorn neighborhood in western Omaha, a city of 485,000 people with a metropolitan-area population of about 1 million.

Staci Roe surveyed the damage to what was supposed to be her “forever home,” which was not even two years old. When the tornado hit, they were at the airport picking up a friend who was supposed to spend the night.

“There was no home to come to,” she said, describing “utter dread” when she saw it for the first time.

Nebraska Gov. Jim Pillen and Iowa Gov. Kim Reynolds spent Saturday touring the damage and arranging for assistance for the damaged communities. Formal damage assessments are still underway, but the states plan to seek federal help.