Christians have been praying after heavy downpours caused the Guadalupe River in Texas to burst its banks on Thursday night, deluging a Christian all-girls summer camp.
At least 51 people, including 15 children, have died in the flooding.
The search continues for 10 girls and one camp counsellor swept away from the Camp Mystic Christian summer camp on the shores of the Guadalupe in Kerr County.
The families of four campers have confirmed their deaths to CNN.
Christian author Beth Moore said she was "undone" over the "tragedy" at Camp Mystic.
"Please pray with me for these beloved children, the families of those confirmed lost and traumatized kids and camp workers," she said, adding that she was "praying with all my heart for miraculous rescues to still be ahead".
Hundreds of people were staying along the Guadalupe River, some at summer camps, others in campsites and RV parks. Many had come to the area to enjoy the 4th of July celebrations on Friday.
But torrential rains that day caused the river to rise more than 20 feet in less than two hours, triggering flash flooding. According to media reports, victims are as young as eight.
Prayer vigils have been taking place in churches and many Christians are responding. The Southern Baptists of Texas Convention has deployed teams to be part of the relief effort in Kerr County and is welcoming donations to support those affected.
Harvest pastor Greg Laurie said the flooding was "absolutely tragic and heartbreaking".
"Let's pray for the first responders tirelessly searching for the children lost in the flood from the camp," he said.
"Let's also lift up the families enduring this unimaginable loss, praying for comfort and strength during this devastating time."
Evangelist Franklin Graham called the tragedy "devastating" and asked people to join him in praying as the rescue effort continues.
"Pray for those who have lost or missing loved ones and for first responders and rescue teams working to save lives," he said.
Ty Badon, who has been searching for his daughter and her friends, told CNN, "Whoever watches this thing - pray."
