(CNN) - A preliminary review by the National Weather Service found that the powerful tornado that ravaged Missouri's capital Wednesday night rated at least an EF-3 on the Enhanced Fujita scale, indicating maximum wind speeds of 160 mph.
The tornado touched down in Jefferson City, around 11:40 p.m. local time, ripping buildings apart and overturning cars. As residents woke Thursday morning they struggled to comprehend the extent of the tornado's strength and the damage it left in its wake.
"When it hit ... it felt like an earthquake," resident Cindy Sandoval-Jakobsen said.
Only about 5% of all tornadoes are rated EF-3 or higher, according to CNN meteorologist Brandon Miller.
The tornado's funnel was wider than its height, and sent debris as high as 13,000 feet into the air when it struck, the National Weather Service said.
At least 20 people were treated for injuries in Jefferson City, and no deaths were reported there, Missouri Gov. Mike Parson said Thursday morning. The city's police Lt. David Williams said later that no one had been reported missing.
Bricks, trees and downed power lines littered parts of the capital Thursday morning.
"Many, many buildings have significant damage, and there's a lot of buildings that have small damage as well. It's very widespread," Jefferson City Mayor Carrie Tergin told CNN.
Mike Moehn, president of the energy provider Ameren Missouri, said there was "significant infrastructure damage" and that there was "a lot of work to do."
Moehn told reporters that Ameren personnel would be working around the clock until power had been restored. The company hoped power would return for all those affected in Jefferson City by Saturday evening.
The destruction in Missouri came as severe weather has ravaged the central United States over the past several days, unleashing twisters, drenching rain, flash flooding and hail.
At least 29 tornadoes have been reported from early Wednesday into Thursday morning, mostly in Missouri and Oklahoma, the National Weather Service said. A total of 171 have been reported since Friday.
Witnesses describe harrowing scenes
In Jefferson City, trees and poles were snapped and tossed like toys. Cars were overturned at a local dealership.
Kayleigh De Rosa told CNN on Thursday morning she was still shaken up after the tornado struck her home the night before, describing the experience as "the worst nightmare."
She and her boyfriend woke up to the sound of the tornado roaring through their open window. "It's one of the loudest sounds I've ever heard," she said.
They ran to the bathroom and sought refuge in their bathtub, getting there seconds before the tornado hit.
"It felt like a train hit my home," De Rosa said. "Our windows and walls were ripped out."
Eric Cunningham, who took shelter in his basement, said the scene outside looked like a "war zone."
"Several structures have damage," he said, "Roofs torn off houses, trees and power lines down."
The president of Lincoln University in Jefferson City said her residence was "unlivable" after the tornado destroyed it.
Jerald Jones Woolfolk said she was in an upstairs bedroom when she heard the sirens and went to the basement, where she said she put her head down and prayed.
After the storm passed, she stepped outside and saw extensive damage.
"Windows knocked out, doors knocked out, a whole back wall came down," she said. "My vehicles are probably totaled."
Some of her furniture was found about a half-mile away from campus.
Tornadoes across Missouri
Golden City, about a three-hour drive southwest of Jefferson City, launched search-and-rescue missions after a possible tornado there.
A tornado also hit near Joplin on the eighth anniversary of the devastating twister that killed 161 people there. According to radar images, the storm passed a few miles north of Joplin, in far southwestern Missouri.
In nearby Carl Junction, Chris Higgins recorded a video of a twister churning just outside his neighborhood during daylight Wednesday.
Elsewhere in Missouri, a husband and wife were killed Tuesday when their SUV skidded across the center lines of US 160 and struck a semi.
A dam is threatened in Tulsa
Severe weather was not limited to tornadoes -- heavy rains have caused flooding in parts of the central United States, including in Oklahoma.
Authorities said Thursday that one death in Payne County was attributable to flooding and 74 people statewide have been hospitalized because of weather-related injuries.
Police in Tulsa, Oklahoma, asked neighborhoods near a dam to prepare for evacuations if they're needed, because officials are intentionally releasing water to relieve pressure on the structure.
The US Army Corps of Engineers was releasing 250,000 cubic feet of water per second Thursday at the dam at Keystone Lake because the water is 31 feet above its normal level.
Tulsa Mayor G.T. Bynum tweeted Wednesday that 215,000 cubic feet of water per second is the minimum rate they can release to keep the water in the reservoir from topping the floodgates. If the floodgates don't work, the dam could fail, Bynum said.
While that dam is about 20 miles from the city, Tulsa authorities told people to be ready to leave their homes quickly if the situation deteriorates.
They also warned residents to stay out of the swollen rivers and creeks.
"Please do not play or walk in the flood waters and make sure your children stay out of the water," a tweet on the city's verified account said. "This is dangerous for many reasons -- strong currents, possible sinkholes, and sewage. There are also several reports of snakes."
Runaway barges smash into dam
On Thursday, two barges that had broken free on the swollen Arkansas River drifted downstream and slammed into the Webbers Falls Lock & Dam, according to Kim Wann, the LeFlore County emergency manager. The barges promptly sank.
They had forced police earlier to close an Interstate 40 bridge near Webbers Falls. The barges were briefly stationary after getting caught on a rock jetty Thursday morning but later broke away again.
No breach in the dam has been identified, Wann said, and state officials and the Army Corps of Engineers are assessing the potential damage.
Because of flooding along the Arkansas River and Bayou Manard, some people in and around the communities of Webbers Falls, Muskogee and Fort Gibson were being evacuated Wednesday, state emergency management spokeswoman Keli Cain said.
Storms have repeatedly hit the same areas recently, making the Plains and the Midwest more vulnerable to flooding.
Serious flooding -- including along the already swollen Mississippi River -- is expected as more rain falls over the region in the next few days.
The high water levels and fast-moving currents led the US Coast Guard on Thursday afternoon to close a portion of the Mississippi River from mile marker 179 to 184 and institute a no wake order along the Illinois River from mile marker 10 to mile marker 80.2.
A no wake order limits the speed of vessels. A vessel must move slowly enough so it doesn't produce a wake behind.
Clarification: This story has been updated to clarify the name of the Missouri capital.
CNN's Joe Sutton, Dave Alsup, Derek Van Dam, Haley Brink, Dave Hennen, Jason Hanna, Paul P. Murphy, Gianluca Mezzofiore and Jamiel Lynch contributed to this report.
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