Texas: Panic-stricken parents in Texas have posted photos of their young daughters on social media requesting for information as more than 20 campers from an all-girls summer camp were unaccounted for on Friday after floods tore through the state's south-central region overnight on Friday.

According to Kerr County Sheriff Larry Leitha, at least 13 people were dead Friday and dozens missing after Texas Hill Country received months worth of heavy rain in a matter of hours. The flood-prone region is dotted with century-old summer camps that see thousands of kids visiting annually from across the Lone Star State.

Lt Gov Dan Patrick said about 23 girls attending Camp Mystic, a Christian camp along the Guadalupe River in Hunt, Texas, were reported missing on Friday afternoon. Search teams were working to conduct helicopter and boat rescues in the fast-moving floodwaters.

“I’m asking the people of Texas, do some serious praying this afternoon — on-your-knees kind of praying — that we find these young girls,” Patrick said.

Distressed families rely on Facebook groups for info

Dozens of families shared in local Facebook groups that they received devastating phone calls from safety officials informing them that their daughters had not yet been located among the washed-away camp cabins and downed trees. Some were waiting to hear if their children could be evacuated by helicopter. Nine rescue teams, 14 helicopters and 12 drones were being used in the search, Patrick said.

Camp Mystic said in an email to parents that if they have not been contacted directly, their child is accounted for. Safety officials said there were roughly 750 campers.

At an elementary school in nearby Ingram that was being used as a reunification center, more than a hundred people milled around a courtyard with hopes of seeing their loved one step out of buses dropping off those who had been evacuated. One young girl wearing a Camp Mystic T-shirt stood in a puddle in her white socks, sobbing in her mother's arms as she rubbed her hands together and watched the buses arrive.

Many families hoped to see loved ones who had been at campgrounds and mobile home parks in the area.

Unique geography makes the valley vulnerable to flash floods

Camp Mystic sits on a strip known as “flash flood alley,” said Austin Dickson, CEO of the Community Foundation of the Texas Hill Country, a charitable endowment that is collecting donations to help nonprofits responding to the disaster.

“When it rains, water doesn’t soak into the soil,” Dickson said. “It rushes down the hill.”

Decades prior, floodwaters engulfed a bus of teenage campers from another Christian camp along the Guadalupe River during devastating summer storms in 1987. A total of 10 campers from Pot O’ Gold Christian camp drowned after their bus was unable to evacuate in time from a site near Comfort, 53 kilometers east of Hunt.

Leaders at Camp Mystic said they are without power, Wi-Fi and running water, and the highway leading to the camp has washed away.

Two other camps on the river, Camp Waldemar and Camp La Junta, said in Instagram posts that all campers and staff there were safe.