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.

At a Glance Severe storms and flash flooding have struck the Plains this weekend.

An EF2 tornado caused damage in Tulsa, Oklahoma.

Flash flooding swamped parts of Kansas City.

No sirens were sounded in Tulsa despite an EF2 tornado that swept through the city early Sunday morning, leaving a trail of damage and injuries in its wake.

"The National Weather Service issued a tornado warning at 1:25 a.m.," the city of Tulsa said in a statement to the Tulsa World. "This particular storm spun up at such a quick rate between scans of the radar and by the time the NWS issued the warning, the storm was crossing into Broken Arrow."

Roger Jolliff, director of the Tulsa Emergency Management agency, told CBS News they did not sound the sirens because the twister had already moved on to the neighboring city.

"I said if it's in Broken Arrow, we will not sound our sirens because the threat at that time that we had got this information... was going into Broken Arrow," Jolliff told CBS.

Tulsa mayor G.T. Bynum said in Facebook post Sunday that city officials gave a "heads up" to officials in Broken Arrow, allowing them to activate their sirens in time.

The tornado left restaurants and storefronts in the mid town portion of Tulsa in ruins, CBS reports, and two people were taken to the hospital with life-threatening injuries.

Around 30 others were transported to St. Francis Hospital for minor injuries sustained in the storm, according to The Associated Press. Emergency Medical Services Authority spokeswoman Kelli Bruer, told the AP eight of the injured were taken from a TGI Fridays restaurant, four from a Whataburger restaurant and one person who was in the area when the storm hit.

"It's a highly commercial area with a lot of people normally in there. There's a mall, there's a movie theater, a TGI Fridays," Meloy said. The area also includes some industrial sites.

There have been numerous reports of damage to roofs, power poles, signs and trees in Tulsa. Interstate 44 on the southeast side of the city was closed after a large overhead sign fell, according to a damage report submitted to the National Weather Service. Promenade Mall will also be closed today due to storm damage, according to Newson6.com.

Crews confirmed the storm caused a gas leak at a Jimmy Johns restaurant in the midtown area, FOX23.com reports. They were able to shut the gas off in the area. More than 12,000 customers had lost power as of Sunday morning, according to the Public Service Company of Oklahoma.

Two smaller twisters hit not long after the first, an EF1 in Broken Arrow and another EF1 in Oologah, respectively.

Despite Oklahoma's place in the heart of Tornado Alley, Jolliff told the Tulsa World he tries to not "over-warn" in his job because studies have shown people stop paying attention to sirens if they sound too often and seemingly without cause.

"We want to be safe (rather) than sorry, but you don’t want to be so safe that you cause other people to lose confidence in the decisions you're making," he said.

Bynum said Sunday that the city will review its siren procedures and protocols .

"After we are done with this cleanup, the City will review our technology and protocols for initiating sirens," Bynum posted. "We will make whatever improvements need to be made to best protect Tulsans."