CNN  — 

At least 21 people are confirmed dead while about 20 others remain missing after severe flooding that swept through Humphreys County in Middle Tennessee, local officials said.

“We’ve experienced devastating loss of life over the last couple days,” Grant Gillespie, the police and fire chief of Waverly, Tennessee, said in a news conference Sunday evening.

Twenty of those killed in the flooding Saturday were confirmed dead within the city of Waverly, the county seat, a news release from the Humphreys County Emergency Management Agency said. One other was confirmed dead elsewhere in the county.

Local officials revised the number of missing down from an earlier count of 45. Gillespie explained the figure was high because the storm had knocked out cell service, making it difficult for people to reach their loved ones.

In a separate news conference in Nashville, Gov. Bill Lee described a “tremendous loss of life” in Waverly, with “homes washed off their foundations, cars strewn around the community.”

“It is a devastating picture of loss and heartache,” he said.

The director of the Tennessee Emergency Management Agency said his agency had confirmed 16 fatalities but acknowledged the discrepancy with local authorities, saying it was due to the state’s validation process.

“You might see a discrepancy in numbers sometimes, what’s coming from the sheriff or what’s coming from our official reports, and it’s really just a matter of process,” Director Patrick Sheehan said. “What we know is there are a number of people still missing.”

The flooding damaged infrastructure, schools, homes and other facilities in Waverly, Gillespie said, adding he believed federal assistance would be needed for the community to recover.

The community needs “patience and prayers,” Humphreys County Sheriff Chris Davis told reporters, asking people to stay out of the area while authorities continue search and rescue operations.

A reunification center has been opened at McEwen High School, where community members can report missing people, the sheriff’s office said. In the meantime, three shelters have been set up in Waverly, at the Waverly Church of Christ, First Baptist Church and Compassion Church, Humphreys County officials said.

An 8 p.m. curfew will remain in place Sunday evening, the statement said.

‘A devastating event’

The deceased range from “the children to the elderly,” Davis previously told CNN affiliate WSMV. He previously told the station that two toddlers were among the dead.

“They just went and got one of my best friends and recovered him. He drowned in this,” the sheriff said, growing emotional. “It’s tough, but we’re going to move forward.”

Casey Hipshire lost her McEwen home in the flooding, telling CNN on Sunday evening that the past day has been filled with “a lot of heartache.”

Hipshire woke up to find the water rising and started praying it wouldn’t get any higher, she said.

“Then it just came so fast, and I packed a bag as quick as I could for all of us,” she said, referring to herself, her husband and her 8-year-old son. “Next thing I know, the water’s in my house and it’s up to my chest.”

“My house fell off the foundation while were still in it, so we had to break the window in the kitchen and crawl out of it and get up on the roof as fast as we could,” she said.

Debris from flooding is strewn along Sam Hollow Road following heavy rainfall on Saturday, August 21, in Dickson, Tennessee.

Hipshire said her family was aware there might be some flooding.

“But I don’t think anybody knew it was going to be this harsh,” she said.

More than 17 inches of rain was measured in McEwen on Saturday, possibly setting a new state record for 24-hour rainfall, though the data still needs to be checked before the new record is official, according to the National Weather Service in Nashville.

Krissy Hurley, warning coordination meteorologist for NWS Nashville, told CNN that’s one-third of the yearly rainfall in a given year.

“We were getting rainfall rates of 3 inches per hour for three hours straight,” Hurley said. “It’s an unheard of, astronomical type of statistic to see after the fact.”

Meteorologists started anticipating heavy rain for the area on Thursday. The initial forecast was about 6 inches of rain, she said, though higher amounts weren’t out of the question.

“Once things started going and developing early Saturday morning, we realized it would be a devastating event,” she said.

Steve Smith, program director and a stormspotter at Huntsville, Alabama’s WZYP, told CNN, “It looked more like a hurricane or tornado had gone through the area.”

Numerous agencies have responded

The impacted counties include Humphreys, Hickman, Houston and Dickson, and drivers were urged to not attempt to cross flood roads, according to the Tennessee Emergency Management Agency.

Numerous state agencies have responded, TEMA said, including the Tennessee National Guard, the state Department of Transportation, the Tennessee Highway Patrol and the Tennessee Department of Health.

Gov. Lee said Waverly has seen a “tremendous outpouring” of help from surrounding communities, with churches opening up to be used as shelters and first responders showing up to help coordinate efforts. TEMA is working with the Tennessee National Guard to establish a donation center in Waverly, Sheehan said.

The Tennessee National Guard said Saturday night it was deploying nearly 50 soldiers to respond to the severe flooding, and that it sent a Blackhawk helicopter to the scene to assist with water rescues. Tactical vehicles and Humvees are also being used in rescue operations.

President Joe Biden on Sunday pledged support for states experiencing extreme weather, including Tennessee, saying the administration would offer any assistance the state needs following the floods.

“I want to begin by expressing my deepest condolences for the sudden and tragic loss of life due to this flash flood,” Biden said. “I know we reached out to the community, and we stand ready to offer them support.”

The deadly flash flooding event – along with the extreme rainfall seen in New York City thanks to Hurricane Henri – are becoming more common due to human-caused global warming, scientists say. A recent UN climate report said the “frequency and intensity of heavy precipitation events have increased since the 1950s over most land area.”

CNN’s Kay Jones, Andy Rose and Alaa Elassar contributed to this report.