(NewsNation) — A massive storm system whipped through the Southern U.S. on Thursday, spawning tornadoes that killed at least nine people in Alabama and Georgia.

Authorities said a clearer picture of the extent of the damage and a search for additional victims would come Friday, when conditions were expected to clear. The “large and extremely dangerous tornado” brought severe damage to several counties as a large storm system moved eastward across the region.

Seven of the deaths were recorded in Autauga County, Alabama, 41 miles northeast of Selma, where an estimated 40 homes were damaged or destroyed by a tornado that cut a 20-mile path across two rural communities, said Ernie Baggett, the county’s emergency management director.

At least 12 people were injured severely enough to be taken to hospitals by emergency responders, Baggett told The Associated Press. He said crews were focused Thursday night on cutting through downed trees to look for people who may need help.

“This is the worst that I’ve seen here in this county,” Baggett said of the damage.

Georgia Gov. Brian Kemp said Friday that a state Department of Transportation worker was killed while responding to storm damage. He gave no further details.

“Unfortunately, it’s been a tragic night and morning in our state. We know we’ve lost two fatalities, and we can confirm one of those was a state employee that was responding to storm damage,” Kemp said during a press conference on Friday.

The governor also said that a 5-year-old was killed when a tree fell on a vehicle in Jackson, Georgia. In the same county southeast of Atlanta, the storm appeared to have knocked a freight train off its tracks, officials said.

Nationwide, there were 33 separate tornado reports from the National Weather Service on Thursday, and Mississippi, Alabama, Georgia, Tennessee, Kentucky, South Carolina and North Carolina all saw tornado warnings for a time. The tornado reports were not yet confirmed and some of them could later be classified as wind damage after assessments are done in the coming days.

About 40,000 customers were without power in Alabama on Thursday night, according to PowerOutage.us, which tracks outages nationwide. About 86,000 customers in Georgia were without electricity after the storm system carved a path across a tier of counties just south of Atlanta.

Kemp said that the tornadoes damaged areas across the entire state and that there are response teams on the ground trying to restore power and assess the damage. Kemp and his team were also expected to take a helicopter tour to assess the damage from above, he said in the conference.

According to the Selma mayor’s office, the city sustained significant damage from the tornado.

“Emergency response teams are on the ground providing assistance and cleaning right of ways,” the mayor’s office posted on social media. “We are asking everyone to stay calm and stay in place until further notice.”

Selma schools went on a weather lockdown as a giant, swirling storm system shredded the walls of homes, toppled roofs and uprooted trees.

Former state Sen. Hank Sanders said he has been told there is damage “all over Selma.”

“A tornado has definitely damaged Selma. In fact, it hit our house, but not head-on. It blew out windows in the bedroom and in the living room. It is raining through the roof in the kitchen,” Sanders said.

Video posted on social media shows the damage, including uprooted trees and debris scattered across streets in several cities.

“Our hearts and thoughts, go out to the Selma community and everyone impacted by the storm,” White House press secretary Karine Jean-Pierre said. “Our team here is monitoring and assessing the situation.”

School systems in at least six Georgia counties canceled classes on Friday. Those systems enroll a total of 90,000 students.

In Kentucky, the National Weather Service in Louisville confirmed that an EF-1 tornado struck Mercer County and said crews were surveying damage in a handful of other counties.

Three factors — a natural La Nina weather cycle, warming of the Gulf of Mexico likely related to climate change and a decadeslong shift of tornadoes from the west to east — came together to make Thursday’s tornado outbreak unusual and damaging, said Victor Gensini, a meteorology professor at Northern Illinois University who studies tornado trends.

The Associated Press contributed to this report.