Some of the dead were children, Texas Lieutenant Governor Dan Patrick said at a previous news conference.
On Saturday, the National Weather Service warned of more extremely heavy rain and "locally catastrophic" flash flooding to come in the region, located northwest of San Antonio.
"Flash flooding is already occurring," the NWS said in an alert, calling on residents to move to higher ground, and to "act quickly to protect your life."
In Kerrville on Saturday, the usually calm Guadalupe River was flowing fast, its murky waters filled with debris.
"It rained in a day what it usually rains in a year," said local resident Gerardo Martinez, 61.
"The water reached the top of the trees. About ten meters or so," he added. "Cars, whole houses were going down the river. That was pretty bad."
- 'Still missing' -
Friday saw a massive rescue operation launched, with around 500 personnel and 14 helicopters helping in the search for survivors.
Texas military official Major General Thomas Suelzer told reporters at least 237 people had been rescued or evacuated by emergency personnel, with 167 rescues performed using helicopters.
On Friday evening, the county sheriff said as many as 25 children from the Camp Mystic Christian summer camp in the flooded Kerr County were missing.
Lieutenant Governor Patrick put the number of missing children at "about 23."
On Saturday, US media reported that two of the missing girls were dead, citing their families.
The Heart O' The Hills summer camp, located about a mile away from Camp Mystic, confirmed on Saturday that its director Jane Ragsdale was among the dead.
They were among the roughly 750 children at Camp Mystic, a girls summer camp along the banks of the Guadalupe River, which rose 26 feet (eight meters) in 45 minutes with heavy rainfall overnight.
"That does not mean they've been lost, they could be in a tree, they could be out of communication," Patrick said.
Texas Governor Greg Abbott has signed a disaster declaration to boost resources for counties in the region, and President Donald Trump has promised federal support.
Vice President JD Vance on Saturday described the disaster as "an incomprehensible tragedy."
- 'Mass casualty event' -
Freeman Martin, director of the state's public safety department, said continuing heavy rain had made conditions challenging for rescuers.
Martin called the disaster a "mass casualty event."
State and local officials warned against residents traveling to the area which includes camp grounds dotted along the river, with dozens of roads impassable.
Videos on social media showed houses and trees swept away by the flash flood caused by heavy overnight rain of up to 12 inches -- one-third of Kerr County's average annual rainfall.
Governor Abbott shared a video on X of a victim being plucked from the top of a tree by a rescuer dangling from a helicopter, as floodwaters raged below.
The Texas National Guard sent rescue teams and the US Coast Guard joined efforts as well.
- 'Another wave' -
Kerr County officials have repeatedly said they were unaware of an impending flood overnight from Thursday to Friday.
"We didn't know this flood was coming," Kerr County judge Rob Kelly said on Friday, adding that the region has "floods all the time."
"This is the most dangerous river valley in the United States," he added, referring to the Guadalupe River.
Soila Reyna, 55, a Kerrville resident who works at a local church helping people who lost their belongings, witnessed the devastation unfold.
"It has been years since we had a flood, but nothing like this," Reyna said.
"Nothing like as catastrophic as this, where it involved children, people and just the loss of people's houses and you know, it's just crazy," she added.
Flash floods, which occur when the ground is unable to absorb torrential rainfall, are not unusual.
But scientists say in recent years human-driven climate change has made extreme weather events like floods, droughts and heat waves more frequent and intense.
In Kerrville, Martinez said Friday's flooding was some of the worst he had ever seen.
"There is a saying here that there's a flood every hundred years," he said. "We had it. We've never seen anything like that and hopefully we won't ever see it again."
