Rescuers searched Saturday for 27 girls missing from a riverside summer camp in Texas, after torrential rains caused devastating floods that killed 50 people in the US state.

Multiple flash flood warnings remained in place across central Texas after water surged through communities, with the Guadalupe River rise by 26 feet (eight meters) in just 45 minutes.

The Kerr County summer camp where hundreds were staying was left in disarray, with blankets, teddy bears and other belongings caked in mud.

"We have recovered 43 deceased individuals in Kerr County. Among these who are deceased we have 28 adults and 15 children," said Larry Leitha, the sheriff of the flood-ravaged region.

Multiple victims were also found in other counties, bringing the death toll to 50.

Texas Department of Emergency Management chief Nim Kidd said air, ground and water-based crews were scouring the length of the Guadalupe River for survivors and the bodies of the dead.

"We will continue the search until all those who are missing are found," he said.

Texas Governor Greg Abbott said he was expanding a state disaster declaration and was requesting additional federal resources from President Donald Trump.

The flooding began Friday — the start of the Fourth of July holiday weekend — as months' worth of rain fell in a matter of hours.

The National Weather Service (NWS) warned that more rain was forecast, and that "excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations."

In Kerrville on Saturday, the usually calm Guadalupe was flowing fast, its murky waters filled with debris. 

"The water reached the top of the trees. About 10 meters or so," said resident Gerardo Martinez, 61. "Cars, whole houses were going down the river."

Flash floods, which occur when the ground is unable to absorb torrential rainfall, are not unusual.

But scientists say that in recent years human-driven climate change has made extreme weather events such as floods, droughts and heatwaves more frequent and more intense.

Devastation at Camp Mystic

On Saturday, Sheriff Leitha said 27 children from Camp Mystic in flooded Kerr County were still missing. Around 750 girls were attending the camp along the banks of the Guadalupe.

US media reported that four of the missing girls were dead, citing their families. 

The windows of camp cabins were shattered, apparently by the force of the water.

Michael, who only gave AFP his first name, was searching the camp for his eight-year-old daughter.

"I was in Austin and drove down yesterday morning, once we heard about it," he said, adding that he was hoping for a "miracle."

The obituary section of the Kerrville community news site was dotted with tributes to victims, including Camp Mystic's owner and director Dick Eastland.

The director of Heart O' The Hills summer camp located about a mile from Camp Mystic, Jane Ragsdale, was also confirmed dead.

Elsewhere in Texas, four people were confirmed dead in Travis County, northeast of Kerr, and 13 people were missing, public information office director Hector Nieto told AFP. 

A 62-year-old woman's body was found in the city of San Angelo in Tom Green County, along the Concho River, police said. 

Two more people died in Burnet County, the area's emergency management coordinator Derek Marchio told AFP, bringing the state-wide death toll to 50.

'Catastrophic'

Department of Homeland Security head Kristi Noem said Trump wanted to "upgrade the technologies" at the weather service and the National Oceanic and Atmospheric Administration (NOAA).

"We need to renew this ancient system," Noem told a press conference.

Scientists and disaster management agencies have criticized Trump for cutting funding and staffing at the NOAA, in charge of weather forecasts and preparedness, and the NWS.

When asked about claims that residents were given insufficient warning of the floods, Noem said she would "carry your concerns back to the federal government."

Officials and residents alike were shocked by the speed and intensity of the flooding.

"We didn't know this flood was coming," Kerr County official Rob Kelly said Friday.

"The predictions were definitely off," and the rain was "double of what was anticipated," Kerrville city official Dalton Rice said.

Rice added that rescuers were facing "very difficult" conditions, and declined to give an overall figure for how many were missing.

Soila Reyna, 55, a Kerrville resident who works at a 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... It's just crazy," she added.

by Moises AVILA