Rescuers were continuing to scour a devastated central Texas landscape of mangled trees, overturned cars and muck-filled debris in an increasingly bleak mission to locate survivors.
The flooding in Kerr County killed at least 43 people, including 15 children, and at least eight people died in nearby counties.
Among the missing are 27 girls who have not been seen since their camp was hit by a wall of water in a historic flash flood.
Authorities have not said how many people are missing beyond the children from Camp Mystic, a Christian summer camp along a river in Kerr County, where most of the dead were recovered.
The destructive, fast-moving waters rose 26 feet on the Guadalupe River in just 45 minutes before daybreak on Friday, washing away homes and vehicles.
The danger was not over as 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 people stranded in trees and from camps isolated by washed-out roads.
Governor Greg Abbott vowed that authorities would work around the clock and said new areas were being searched as the water receded.
He declared Sunday a day of prayer for the state.
“I urge every Texan to join me in prayer this Sunday — for the lives lost, for those still missing, for the recovery of our communities, and for the safety of those on the front lines,” he said in a statement.
Authorities were coming under scrutiny about whether the camps and residents in places long vulnerable to flooding had 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 swum and spent time outdoors.
The area is especially popular around the July 4 holiday, making it more difficult to know how many are missing.
“We don’t even want to begin to estimate at this time,” Kerrville city manager Dalton Rice said previously.