In what experts call "Flash Flood Alley," the terrain reacts quickly to rainfall steep slopes, rocky ground, and narrow riverbeds leave little time for warning.

Also: San Antonio mourned the victims in a Travis Park vigil; UTSA said one of its teachers died in the Guadalupe River flood; Kerrville officials said a privately owned drone collided with a helicopter conducting search and rescue operations.

Brooklyn and Bailey McKnight's little sister, Paisley, was at a camp on a smaller arm of the Guadalupe River. The 14-year-old was "just miles" away from Camp Mystic in Central Texas, which has been devastated by the deadly floodwaters spurred by extreme rainfall on July 4.

Texas inspectors approved Camp Mystic’s emergency plan just two days before devastating floods killed over 27 people, mostly children, at the Texas summer camp

Six North Texas girls missing from Camp Mystic in the wake of catastrophic Central Texas flooding have been confirmed dead, their families confirmed.