KERRVILLE, Texas — Months worth of heavy rain fell in a matter of hours on Texas Hill Country, leaving 24 people dead and many more unaccounted for Friday, including more than 20 girls attending a summer camp, as search teams conducted boat and helicopter rescues in fast-moving floodwaters.

Desperate pleas peppered social media as loved ones sought any information about people caught in the flood zone. At least 25 centimeters of rain poured down overnight in central Kerr County, causing flash flooding of the Guadalupe River.

At a news conference late Friday Kerr County Sheriff Larry Leitha said 24 people had been killed. Authorities said 237 people had been recued so far, including 167 by helicopter.

The missing children were attending Camp Mystic, a Christian camp along the Guadalupe River in the small town of Hunt. Elinor Lester, 13, said she and her cabin mates had to be helicoptered to safety.

A raging storm woke up her cabin around 1:30 am, and when rescuers arrived, Lester said they tied a rope for the girls to hold as the children in her cabin walked across bridge with floodwaters whipping around the calves and knees.

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“The camp was completely destroyed,” she said. “A helicopter landed and started taking people away. It was really scary.” The situation was still developing and officials said the death toll could change, with rescue operations ongoing for an unspecified total number of missing.

Authorities were still working to identify the dead.

Pleading for information after flash flood A river gauge at Hunt recorded 6.7 meters in about two hours, according to Bob Fogarty, meteorologist with the National Weather Service’s Austin/San Antonio office. The gauge failed after recording a level of 9 meters.

“The water’s moving so fast, you’re not going to recognize how bad it is until it’s on top of you,” Fogarty said.

On the Kerr County sheriff's office Facebook page, people posted pictures of loved ones and begged for help finding them.

At least 400 people were on the ground helping in the response, Texas Lt. Gov. Dan Patrick said. Nine rescue teams, 14 helicopters and 12 drones were being used, with some people being rescued from trees.

About 23 of the roughly 750 girls attending Camp Mystic were among those who were unaccounted for, Patrick said.

Search crews were doing “whatever we can do to find everyone we can,” he said.

‘Pitch black wall of death’

In Ingram, Erin Burgess woke to thunder and rain at 3:30 am. Just 20 minutes later, water was pouring into her home directly across from the river, she said. She described an agonizing hour clinging to a tree and waiting for the water to recede enough so they could walk up the hill to a neighbor's home.

“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.

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Of her 19-year-old son, Burgess said: “Thankfully he’s over 6 feet tall. That’s the only thing that saved me, was hanging on to him.” Matthew Stone, 44, of Kerrville, said police came knocking on doors at 5:30 a.m. but that he had received no warning on his phone.

“We got no emergency alert. There was nothing," Stone said.

‘Scared to death’

At a reunification center set up in Ingram, families cried and cheered as loved ones got off vehicles loaded with evacuees. Two soldiers carried an older woman who could not get down a ladder. Behind her, a woman in a soiled T-shirt and shorts clutched a small white dog.

Later, a girl in a white “Camp Mystic” T-shirt and white socks stood in a puddle, sobbing in her mother’s arms.

Barry Adelman, 54, said water pushed everyone in his three-story house into the attic, including his 94-year-old grandmother and 9-year-old grandson. The water started coming through the attic floor before finally receding.

“I was horrified,” he said. “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.”

‘No one knew this kind of flood was coming’

The forecast had called for rain, with a flood watch upgraded to a warning overnight for at least 30,000 people. But totals in some places exceeded expectations, said Fogarty.

Patrick noted that the potential for heavy rain and flooding covered a large area.

Asked about how people were notified in Kerr County so that they could get to safety, Judge Rob Kelly, the county's chief elected official, said: “We do not have a warning system.”

When reporters pushed on why more precautions weren't taken, Kelly responded: “Rest assured, no one knew this kind of flood was coming.” “We have floods all the time," he added.