(CNN) — Rescue crews searched Thursday for seven people missing after overnight tornadoes struck North Texas, killing at least six.
"We're still working to identify people," Hood County Sheriff Roger Deeds told reporters about the fatalities, all of whom were adults.
It was not clear whether the toll would rise. Rescue crews had walked through one subdivision in the city of Granbury "over and over and over again," he said. "I'm confident we haven't left anybody behind, but we're still checking." Granbury is 40 miles southwest of Fort Worth.
The six victims were in a Habitat for Humanity neighborhood of about 110 homes -- most of which were destroyed -- called the Rancho Brazos subdivision, the sheriff said. That is where the missing were last seen, too, he said.
Three people were taken to an area hospital, and 13 others were taken to hospitals in the Dallas-Fort Worth metroplex, he said.
At least 10 tornadoes touched down overnight in the area, the National Weather Service said. A weather service survey team said it found damage indicating an EF4 tornado had struck. That is the second-most severe classification on a scale of 0 to 5.
"The main concern is life safety and finding any victims that still need our help, making sure we tend to those victims and their pets, too," Deeds said.
There were reports of homes in Granbury being flattened with people inside, Hood County Judge Darrell Cockerham said.
In nearby Ellis County, a suspected tornado knocked out power in the city of Ennis about midnight, said Steve Howerton, city manager.
"Several buildings in the downtown historic district have been seriously damaged," he said.
"There are a lot of traumatic injuries," said Donna Martin, a worker at a local veterans' organization. "My husband told me that a car was lifted in the air. It just came in and hit so fast."
B.B. French, who lives on a canal three miles from where the worst of the damage occurred, said she was lucky.
"We had extreme winds," the 71-year-old resident told CNN in a telephone interview. "And then the sirens went off and then I got inside."
As lightning flashed and rain poured, she watched from inside her home as two mallards lay on the pavement. "They just laid down on the sidewalk until the hail came, and then they were smart enough to waddle over and get underneath the roof" of her boat deck.
After the storm passed, she went outside to find that her neighbor on one side had lost a few shingles from his roof; on the other side, a neighbor had lost a couple of shutters; but her house was unscathed.
"It really is just luck," she said.