(NEW YORK) -- Four people were killed and at least 35 were injured after a powerful tornado devastated Greenfield, Iowa, state police announced Wednesday.
Officials in Iowa's Adair County made the announcement about 24 hours after the twister hit the small town of Greenfield.
The names and ages of those killed in the severe weather event are not being released at this time, officials said.
Over the past 24 hours, tornadoes have been reported in Iowa, Nebraska, Missouri, Oklahoma, Wisconsin and Minnesota -- with a majority of the reports stemming from Iowa.
According to the National Weather Service, at least 21 of the 26 reported tornadoes spawned by severe weather on Tuesday struck Iowa between 5:44 p.m. and 11 p.m. CT.
"It's just gut-wrenching. It's horrific. It's hard to describe until you can actually see it, the devastation," Iowa Gov. Kim Reynolds said at a news conference in Greenfield Wednesday morning.
She said that much of the town of Greenfield was flattened in Tuesday's severe weather event.
The tornado that struck Greenfield was preliminarily confirmed by the National Weather Service as an EF-3 on the Enhanced Fujita Scale, with maximum wind speeds reaching 135 mph.
The Adair County Memorial Hospital, which serves Greenfield, sustained tornado damage, one official said Tuesday night, but workers still managed to treat patients and transport some to nearby hospitals for further care.
On Wednesday, the hospital released a statement saying the damage from the tornado required staff and patients to be evacuated from the facility.
The hospital will remain closed for weeks, if not months, to assess the damage and repair the building, according to the statement.
Neither staff nor patients were injured during the storm, according to hospital officials.
State Rep. Ray Sorensen, who represents Greenfield, said he was painting at a church when the tornado struck around 3 p.m. Tuesday and rushed into town to find numerous homes damaged or completely demolished and nearly all of the historic trees in Greenfield uprooted and stripped of limbs.
"It's a completely different town now," Sorensen said.
But he said that when he arrived at the scene of the devastation, people were already clearing the streets of debris to make way for emergency vehicles and helping those injured get medical attention at a makeshift triage center at a lumber yard.
"Everybody became little makeshift ambulances," Sorensen said. "We pulled a guy from the rubble and put him on a little makeshift stretcher that we made, threw him in the back of a truck of a guy that isn’t even from Iowa and we just made our way to the lumber yard, which was the makeshift hospital."
At least 329 severe storms were reported Tuesday through the nation's midsection from Texas to Michigan, even up in New England.
More severe weather is on the way. The highest threat for tornadoes, damaging winds and large hail will be in Texas, Oklahoma, Arkansas and Louisiana, including major cities such as Dallas, Waco, Abilene, Little Rock and Shreveport.
Some damaging winds could also develop in Memphis, Nashville, Louisville, Cincinnati, Pittsburgh, Buffalo and Rochester.
Severe weather is also expected to stretch into Thursday as the Memorial Day weekend gets underway. Dangerous weather is expected on Thursday through large parts of the Heartland and parts of the South from South Dakota to Texas and east to Tennessee.
Temple City, Texas, which is located between Austin and Waco, issued an emergency declaration on Wednesday night. The Wilson Recreation Center in the area was turned into a makeshift shelter, officials said on Facebook.
On Tuesday, the National Weather Service issued tornado watches for parts of Nebraska, Iowa, South Dakota, Missouri, Arkansas, Wisconsin, Illinois, Minnesota, Kansas and Oklahoma.
Nearly the entire state of Iowa was under a "Particularly Dangerous Situation," according to the National Weather Service, which issued several tornado warnings before the town of Greenfield was slammed by a funnel cloud.
Gov. Reynolds authorized a proclamation of disaster emergency for 15 counties across the state. On Wednesday, she said the state will ask President Joe Biden to approve federal disaster relief.
The counties include Adair, Adams, Cass, Clay, Hardin, Harrison, Jasper, Kossuth, Marshall, Montgomery, Page, Palo Alto, Pottawattamie, Tama and Warren.
Several videos obtained by ABC affiliate station WOI-DT in Des Moines captured a large funnel cloud on the ground in Greenfield.
On Tuesday, WOI reporter Dana Searles, surveying the damage in Des Moines, said, "This small community has a big chunk destroyed, but about half of it is still intact. From what I've seen, I'd estimate that maybe 75% of it is near to the ground right now."
In Yuma, in northeast Colorado, hail ranging from golf ball to softball size pummeled the area, causing damage to cars and buildings. At one point, the hail was so deep it caused multiple vehicles to get stuck, JJ Unger, a volunteer Yuma firefighter, told ABC News Tuesday.
"It was like a blizzard hitting for a half hour because of the hail," Unger said. "That's the longest I've seen it hail like that."
Unger said he and his fire crew were out spotting for possible tornadoes Monday evening when lightning struck.
"It was very intense," said Unger, adding that he and his crew had to pull over and seek shelter as visibility went to almost zero.
Unger said that when the hail finally let up, a foot of hail was covering his fire engine and roads in the area.
He said the windshields of his pickup truck and his wife's vehicle were shattered.
"Almost every home in town has broken windows and I've heard that over a thousand cars were damaged," Unger said.
In Nebraska, hail measuring two inches in diameter fell in Dundy County in the southwest corner of the state, according to local emergency management officials. Winds of over 90 mph were also reported.
More than half a foot of rain was recorded in Omaha, Nebraska, on Tuesday, producing major flash flooding in the area.