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Rescue workers on Saturday continued their frantic search for survivors of the deadly and historic floods unleashed when the Guadalupe River burst from its banks in Kerr County on Friday. At least 27 people have died, including 18 adults and nine children. More than 20 girls from a private Christian summer camp were still missing.

The downpour on Friday caused the river to rise as much as 25 feet in 45 minutes, sending cars and the debris of uprooted trees and shattered buildings all swirling through the gray and brown water.

At a Saturday morning press conference, state and county officials updated the number of fatalities but did not have new information on the missing girls, who were from the 99 year old Camp Mystic, a riverside retreat that contained about 750 campers. Officials said on Friday that some of those campers may be stranded and unable to call for help.

Emergency officials said on Saturday that 850 people were rescued.

Many distraught parents on Saturday still waited for word on their children. Tanya Powell said Ella Rose, her 21 year old daughter, was still missing.

RELATED: Houston-area residents among those reported missing in deadly floods in Texas Hill Country

“She was near the camp in a house with three of her friends,” she explained. “They go to school. They’re college seniors in San Antonio. And they were here for the weekend, and we lost touch with them about 4 a.m. and haven’t gotten any word from them.”

The state has deployed hundreds of search and rescue personnel and more than dozen helicopters into the inundated region, with a focus on boys and girls summer camps, parks, and low-lying subdivisions. Boats raced up the Guadalupe looking for survivors on the riverbanks and even in the trees. First responders set up stations where people who had lost or damaged homes could come for a meal and assistance.

Gov. Greg Abbott said the state would spare no resource to rescue the missing: “So many people have been swept up into an extraordinary catastrophe. It needs God, but it also needs a robust response by the state and local governments and by people who live in these communities impacted by this.”

Abbott continued: “[The rescues] will continue in the darkness of night. They will be taking place when the sun rises in the morning. They will be nonstop seeking to find everybody who is unaccounted for. We will stop at nothing to ensure that every asset and person and plane and whatever is needed is going to be involved in the process of rescuing every last person and assure everybody involved in this is going to be fully accounted for.”

He signed a disaster declaration for Kerr and 13 other counties impacted by Friday’s flooding, enabling them to access state resources for the emergency operations.

By Friday evening, some children were back in their relieved families’ arms. Sympathetic people on social media also shared fragments of information or photos of dazed and nervous children safely gathered in rooms, like a fire station, awaiting reunion with their loved ones.

Forecasters warned more rain was falling the soaked region, nicknamed “flash flood alley.” On Saturday morning, the National Weather Service (NWS) issued a flash flood emergency — a rare warning — in Burnet County after five to 12 inches of rain fell, and more was on the way.

The entire region remained under a flood watch through 7 p.m. There was a 60% chance of more rain, including for Kerr County.

Forecasters urged anyone near a flooded creek or stream to flee — disturbing echoes of the warnings issued on Friday morning before the mass casualty event consumed the Independence Day holiday and left dozens dead or missing.

Videos of the hissing and churning floodwaters dominated social media. Most appeared to have been shot from riverbanks or bridges. They showed fast moving waters filled with wreckage and vegetation, plowing down riverside brush and trees. One showed a recreational vehicle adrift in the water, only a foot or two of the vehicle above the foamy surface. Another showed rising floodwaters slowly swallowing a sign that read “Mandatory Water Restrictions: Stage 2.”

Preparation before the storm

Kerrville city officials pushed back against criticism on Friday afternoon that more could have been done to evacuate before the flood hit the region, known as Flash Flood Alley.

Rice, the Kerrville city manager, told reporters the flooding situation evolved quickly. He said the north and south fork that feed into the Guadalupe River reached peaks at about 3:30 on Friday morning.

“I was on the river trail at that time and everything was fine,” he explained. “Within an hour [or] two hour period, the water was up almost to the bridge.”

Rice said the city had crews out early in the morning to prepare for the Fourth of July celebration, and they were also caught off guard.

“Despite flood warnings, despite everything that was going on, there were some things that happened very fast,” he added.

When asked if a warning system was in effect Thursday night when the flooding started. Rob Kelly, the Kerr County judge, said, “We do not have a warning system on the river. … We didn’t know this flood was coming. Rest assured, no one knew this kind of flood was coming. We have floods all the time.”

He also said that “this is the most dangerous river valley in the United States” but that county officials had “no reason to believe that this was going to be anything like what’s happened here. None whatsoever.”

The NWS had estimated on Thursday that the region might see five to seven inches of rain with the possibility of storm clusters forming over the region. However, the area ended up seeing more than a foot of rain.

How it happened

Jason Runyen, a meteorologist with the NWS, explained the storms were the result of two different factors:

“The first being some high amounts of moisture for this time of year — some near records of moisture — vertically into the atmosphere. The second were the remnants of a midlevel disturbance from what used to be Tropical Storm Barry. So a combination of that disturbance and these record levels of moisture have led to the very heavy rainfall, especially over Kerr County.”

All that rainfall on Friday drained into the Guadalupe River Basin. He said it started up by the headwaters near Hunt, Texas, in western Kerr County and “traveled downstream through Kerrville where it crested” and then traveled toward Comfort.

“We saw some pretty sharp and steep rises on the river,” he added, “in some cases rivaling the 1987 flood, the famous 1987 flood.” The 1987 flood dropped 11 inches of rain, and 10 teenagers died when their church bus ran into flood waters.

Friday’s floods, Runyen said, were so high and forceful that some of the river instrumentation and gauges were affected or washed out. “So it’s a pretty catastrophic type flood wave coming down the Guadalupe River.”

Because of the damaged river gauges, it may take the U.S. Geological Survey a few days to get accurate data on how high the river crested in the Hunt and Kerrville area.

He said some parts of the Hill Country were placed under a rare flash flood emergency, which is different from a flash flood warning.

“Typically most people are familiar with flash flood warnings,” he said. “Our typical flash flood warnings are when we expect imminent flooding in areas — rises and streams and creeks that go over low water crossing.”

Flash flood emergencies, Runyen explained, are “saved for days where we’re expecting catastrophic type damage or widespread damage or even loss of life.”

NPR’s Sergio Martinez-Beltran contributed to this report.