Rescuers scoured flooded riverbanks littered with mangled trees and turned over rocks in the search for more than two dozen children from a girls’ camp and many others missing after a wall of water blasted down a river in the Texas Hill Country.
The storm killed at least 32 people, including 14 children.
The destructive fast-moving waters rose 26 feet (eight metres) in just 45 minutes before daybreak Friday, washing away homes and vehicles.
The danger was not over as torrential rains continued pounding communities outside San Antonio on Saturday and flash flood warnings and watches remained in effect.
Searchers used helicopters, boats and drones to look for victims and to rescue stranded people in trees and from camps isolated by washed-out roads.
“We will not stop until we find everyone who is missing,” Nim Kidd, chief of Texas Department of Emergency Management, said at a press conference on Saturday afternoon.
Kerr County Sheriff Larry Leitha said the bodies of 32 people had been recovered so far: 18 adults and 14 children.
Authorities were coming under growing scrutiny Saturday over whether the camps and residents in places long vulnerable to flooding received proper warning and whether enough preparations were made.
The hills along the Guadalupe River in central Texas are dotted with century-old youth camps and campgrounds where generations of families have come to swim and enjoy the outdoors.
The area is especially popular around the July Fourth holiday, making it more difficult to know how many are missing.
“We don’t even want to begin to estimate at this time,” said City Manager Dalton Rice said on Saturday morning.
Some 27 children were among the missing from Camp Mystic, a Christian summer camp along the river, he said.
“The camp was completely destroyed,” said Elinor Lester, 13, one of hundreds of campers. “A helicopter landed and started taking people away. It was really scary.”
A raging storm fuelled by incredible amounts of moisture woke up her cabin just after midnight Friday, and when rescuers arrived, they tied a rope for the girls to hold as they walked across a bridge with water whipping around their legs, she said.
Frantic parents and families posted photos of missing loved ones and pleas for information.
On Saturday, the camp was mostly deserted.
Helicopters roared above as a few people looked at the damage, including a pickup vehicle tossed onto its side and a building missing its entire front wall.
Among those confirmed dead were an eight-year-old girl from Mountain Brook, Alabama, who was staying at Camp Mystic, and the director of another camp just up the road.
The flooding in the middle of the night caught many residents, campers and officials by surprise in the Hill Country, which sits northwest of San Antonio.
AccuWeather said the private forecasting company and the National Weather Service sent warnings about potential flash flooding hours before the devastation.
“These warnings should have provided officials with ample time to evacuate camps such as Camp Mystic and get people to safety,” AccuWeather said in a statement that called the Hill Country one of the most flash-flood-prone areas of the US because of its terrain and many water crossings.
Officials defended their actions while saying they had not expected such an intense downpour that was the equivalent of months’ worth of rain for the area.
One National Weather Service forecast earlier in the week “did not predict the amount of rain that we saw”, said Nim Kidd, chief of the Texas Division of Emergency Management.
Search crews were facing harsh conditions while “looking in every possible location,” Mr Rice said.
Authorities said about 850 people had been rescued.
US Coast Guard helicopters were flying in to assist.
One reunification centre at an elementary school was mostly quiet Saturday after taking in hundreds of evacuees the day before.
“We still have people coming here looking for their loved ones. We’ve had a little success, but not much,” said Bobby Templeton, superintendent of Ingram Independent School District.
President Donald Trump said Saturday that Homeland Security Secretary Kristi Noem was travelling to Texas and his administration was working with officials on the ground.
“Melania and I are praying for all of the families impacted by this horrible tragedy,” Mr Trump said in a statement on his social media network.
In Ingram, Erin Burgess woke to thunder and rain in the middle of the night Friday. Just 20 minutes later, water was pouring into her home, she said. She described an agonizing hour clinging to a tree with her teenage son.
“My son and I floated to a tree where we hung onto it, and my boyfriend and my dog floated away. He was lost for a while, but we found them,” she said.
Barry Adelman said water pushed everyone in his three-story house into the attic, including his 94-year-old grandmother and nine-year-old grandson.
“I was having to look at my grandson in the face and tell him everything was going to be OK, but inside I was scared to death,” he said.
“When it rains, water doesn’t soak into the soil,” said Austin Dickson, chief executive of the Community Foundation of the Texas Hill Country, which was collecting donations.
“It rushes down the hill.”
The forecast for the weekend had called for rain, with a flood watch upgraded to a warning overnight Friday for at least 30,000 people.
Texas Lieutenant Governor Dan Patrick said the potential for heavy rain and flooding covered a large area.
“Everything was done to give them a heads up that you could have heavy rain, and we’re not exactly sure where it’s going to land,” Mr Patrick said.
“Obviously as it got dark last night, we got into the wee morning of the hours, that’s when the storm started to zero in.”
Kerr County Judge Rob Kelly, the county’s chief elected official, said: “We do not have a warning system.”
When pushed on why more precautions were not taken, Mr Kelly said no one knew this kind of flood was coming.
The slow-moving storm is bringing more rain Saturday, with the potential for pockets of heavy downpours and more flooding, said Jason Runyen, of the National Weather Service.
The threat could linger overnight and into Sunday morning, he said.
