Hailey Chavarria sat Sunday outside a church providing shelter for survivors of the Fourth of July flash flood, and for families like hers who had rushed to Kerrville, Texas, hoping and praying for loved ones they had lost touch with.

For Ms. Chavarria, 28, a teacher from Austin, the wait has been agonizing. Five members of her family from Midland, Texas — her mother, her mother’s husband, an aunt, the aunt’s husband and a cousin — remained missing three days after a torrent of water smashed through their campsite along the Guadalupe River, where they had gathered for what was supposed to be a festive holiday camping trip.

Only one family member, a 22-year-old cousin, Devyn Smith, was found alive, desperately clinging to a tree. Her rescue was captured on video, a moment for celebration in days with few of them. She had been dragged downriver more than 15 miles, through three dams, past broken R.V.s and refrigerators, from 4 a.m. to about 10 a.m. on Friday.

Ms. Smith remains hospitalized, Ms. Chavarria said, with staples in her head and “every inch of her body” scratched and battered.