Video from London showed extensive damage with multiple homes destroyed and vehicles barely recognizable as debris littered the neighborhood and lightning still flashed in the background.

"(My daughter) got scared, so we went to the hallway," a woman named Leslie, who survived the storm with her family, told emergency officials in the video. "And we were in there about two minutes and then my husband came running in and pretty much jumped on top of her because you could feel the air sucking in, and it sounded like a train. And then we saw stuff falling, and next thing you knew, most of the house was gone."

London mayor Randall Weddle posted several photos from an aerial tour of the damage given by Air Evac Life Team, which itself lost its hanger and one of its helicopters to the tornado.

Photos show wide swaths of damaged buildings across the London Corbin airport and into surrounding neighborhoods.

The tornado's size became even more evident as it tore a path through wooded areas on the outskirts of town, leaving a stripe of bare, wind-blasted trees in its wake.

Rescue crews were also combing through tornado damage in Somerset, where at least one person died.

Somerset mayor Alan Keck declared a state of emergency in his city as "damage is extensive and loss of life occurred, the extent of which is not fully reported as of this (declaration)."

"It was a really scary night," Keck told FOX Weather Saturday morning. "This really hit our business community, (the tornado) went right through our commercial corridor. It was a tough night."

While at least one person died in the storms in his city, Keck said the tornado spared hundreds of homes.

"I want to start with some gratitude that it could have been so much worse," he said. "If you look at the path through Somerset, candidly, it's remarkable that it didn't do more damage to residential homes... There were close to 200 apartments right behind (the tornado path) that didn't get hit. It was almost as if the storm lifted up before it got to the next neighborhood… It really could have been monumentally worse."

Beshar warned his state's death toll was expected to rise as the state remains in an active rescue phase. Over 100,000 people in Kentucky remain without power and five counties are in a state of emergency. He plans to visit London to survey the damage later Saturday.

"Please pray for all of our affected families," he said.

The severe weather outbreak began earlier Friday in Missouri as supercell thunderstorms spawned deadly tornadoes.

St. Louis Mayor Cara Spencer said at least five storm-related fatalities have been confirmed in her city. She implemented a city-wide curfew because over 5,000 homes were affected by the storms.

In Scott County, located about 2 hours south of St. Louis, the sheriff reported at least two storm-related deaths and multiple injuries.

"Today, our county was struck by a devastating tornado in the southern region, causing significant damage to several rural areas," Scott County Sheriff Derick Wheetley said. The tornado moved from the eastern part of the county, leaving behind a trail of destruction, with multiple homes completely lost and areas left unrecognizable."

Much of the damage in the St. Louis area seems to have happened in the University City area. FOX News Multimedia Reporter Olivianna Calmes found damage in Clayton, just south of University City. She said she has seen several trees damaged, and some trees have fallen on cars in the area.

"The skies turned green," Rachel, a resident of Clayton, told Calmes. "The winds started whipping. Then, it fell silent, and then you heard what sounded like a train, and everything started falling.

According to a Facebook post, the St. Louis Zoo sustained damage during the storm and will be closed through Saturday.

"All animals are safe and accounted for, and there have been no reports of significant injuries to staff, guests or animals," zoo staff wrote in the post.

The NWS described the storm as a "Particularly Dangerous Situation" when it issued a Tornado Warning that affected more than a million people across the St. Louis metro area.

Tornadic thunderstorms also impacted southern Indiana and Illinois, where several counties south of Interstate 70 were placed under Tornado Warnings.

Sheriff's deputies in Indiana's Monroe County, home to Bloomington, reported six injuries in the storm. At least 75 homes suffered damage, as well as a 30-room motel, a multi-unit duplex property and the Clear Creek post office.

The SPC received more than half a dozen reports of tornado touchdowns in Indiana, but there were no reports of any fatalities connected to the severe weather.

Overall, more than 800,000 customers were reported without power across at least a dozen states, with outages likely to last days in hard-hit communities.

The hard-hit Ohio Valley will get a break from severe storms Saturday as the threat shifts into inland New England, where damaging wind gusts look to be the largest threat from any severe thunderstorms, the FOX Forecast Center said.

Another threat of severe weather energizes in the Southern Plains on Saturday, kicking off another multiday threat across the region.

The Storm Prediction Center has highlighted the potential for severe weather in several areas of the country through early next week.

"This is a classic severe weather setup for the Central Plains," Merwin said. "You have all of that moisture streaming in from the Gulf, the cooler, drier air off the Rockies, and then you get that classic clash zone."