00:48 Sioux Falls Tornado Rips Apart Building in Newly Released Footage Newly released footage from inside a health center in Sioux Falls shows the damage done by an EF-2 tornado that struck the city one year ago.

It was a Mother's Day that residents of several Great Plains towns will never forget.

More than two dozen reported tornadoes were spotted Sunday up and down the Plains, ripping up trees, power lines and, in some cases, chunks of small towns. Where the tornadoes didn't hit, slow-moving storms brought torrential rainfall that flooded other areas, creating another life-threatening danger.

Sunday night, three towns sustained major storm damage: Van, Texas, Nashville, Arkansas, and Lake City, Iowa. Earlier Sunday, the small South Dakota town of Delmont was partially destroyed by a large twister.

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So far, 6 deaths have been reported from this round of severe weather. Here are the latest impacts on a state-by-state basis.

Arkansas

Two people died in Howard County and two others were critically injured after a round of storms rolled through the area Sunday night. The two fatalities occurred in a mobile home park in the town of Nashville, according to the National Weather Service.

Howard County Coroner John Gray told the Associated Press that the two people killed were a young couple, but their toddler-age daughter survived. The couple has been identified as Melissa and Michael Mooneyhan , according to KTBS.com.

An NWS survey crew reviewed the damage Monday afternoon and gave the tornado a preliminary EF2 rating, with maximum wind speeds of at least 125 mph.

Iowa

Just before 8:45 p.m. Eastern time Sunday night, a trained spotter reported a tornado in Lake City, about 100 miles from Des Moines, according to the National Weather Service. The tornado ripped off part of South Central Calhoun High School's roof. When the tornado struck, 150 people were inside the school for an awards ceremony, according to the Des Moines Register.

"The lights went off, and everyone's ears kind of popped," Dave Birks, the school's girls' basketball head coach, said in the report. "They say a tornado sounds like a freight train, and that lasted only 5 or 10 seconds. Everyone came upstairs, and it was a mess."

Before the tornado hit, everyone inside the school hunkered down in the basement and locker rooms, the report added, and no major injuries were reported. Outside the building, the tornado carved a damage path two blocks wide, including the school's roof.

Jodi Simpson, spokesperson for the Calhoun County Sheriff, told The Weather Channel that the town is without power, but no injuries had been reported as of early Monday morning. A survey crew with the NWS gave the tornado a preliminary EF1 rating after viewing the damage. The report said the twister had maximum winds of at least 100 mph.

Gov. Terry Branstad declared a disaster emergency in Calhoun County, allowing state resources to be used in recovery efforts, the AP reported.

South Dakota

Sunday morning, a large reported tornado left damage and injuries in Delmont , according to local emergency officials. The storm, which left the town without power or water, hit the state on the same morning as Winter Storm Venus , which dumped more than a foot of snow in some areas.

An NWS survey crew has completed its review of the damage and rated the tornado EF2 with maximum winds of 130 mph.

Delmont is located in southern South Dakota, about 90 miles southwest of Sioux Falls.

Click here for full coverage of this tornado.

Texas

Gov. Greg Abbott declared a state of disaster in Texas counties Monday, following recent days of severe weather, which has included tornadoes, thunderstorms and flooding.

The declaration, which authorizes further mobilization of state resources to assist impacted communities, included Bosque, Clay, Denton, Eastland, Gaines, Montague and Van Zandt counties.

"Our thoughts and prayers are with those who have lost their lives, their families and all of our affected communities," Abbott said. "I want to thank the first responders who are working tirelessly to provide shelter, care and resources to impacted areas."

Residents of Van experienced a terrifying night after a large killer tornado ripped through the town Sunday night, damaging nearly one-third of the city. The National Weather Service believes the twister was likely an EF3; investigators were still on the scene assessing damage Monday afternoon.

After a night of search-and-rescue operations in the town of about 2,500, authorities confirmed 2 deaths and 43 injuries in Van, and some of those injuries were critical. Eight people remained unaccounted for at the time of the update, early Monday afternoon.

"Damages range from completely destroyed homes, damaged homes, to trees and power lines down," Van Zandt County fire marshal and emergency management coordinator Chuck Allen told the AP in an email.

About 2 hours after the tornado came through the town, another storm forced emergency workers to take cover , according to the Van Fire Department's Facebook page.

Crews will dispatch dogs to search for the missing residents on Monday, according to WFAA.

The American Red Cross opened a shelter at First Baptist Church, and the Van Independent School District announced schools will be closed Monday.

In the "Big Country," an area of Texas composed of 19 counties and centered around Abilene, there hadn't been a killer tornado since 1986. That streak ended Saturday, when a tornado plowed through the town of Cisco, killing one person.

Damage to property has been reported throughout the area and some people are unaccounted for as of mid-day Sunday, Eastland County Judge Rex Fields told the Associated Press. He told the AP that damage assessment has been difficult Saturday because of heavy rains.

"The homes that I've seen, there are just maybe one or two walls standing," he said in the AP report.

Another tornado was reported Sunday in Denton, and the NWS confirmed it was EF1 strength with winds as high as 100 mph after a damage survey.

Flooding was also a major concern in the Lone Star State, as several days of rain were washing out roadways and water rescues were necessary. One person died due to flooding in Corsicana, The Weather Channel confirmed.

The man in his 20s died when he left his car that got stuck in floodwaters , according to NBC DFW. He was swept away and killed by the flooding.