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.

This map shows where camps along the Guadalupe River were impacted by the July 4 flood. Meteorologists Pat Cavlin and Kim Castro detail how it all happened.

The Texas Hill Country has been notorious for flash floods caused by the Guadalupe River. Here's why the area is called "Flash Flood Alley."

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.

Along the Guadalupe River, a 60-room inn and nearby homes were quickly filling with water. Confusion, desperation and heroism ensued.

Follow along for developments on the July Fourth floods along the Guadalupe River in Kerr County and Central Texas.

A Mobile couple visiting their son and his family in Texas are among those still missing. Their daughter-in-law's body was found on Tuesday

Recordings provided to CBS News showed first responders asking for an emergency alert to be sent, but dispatchers delayed because they needed special authorization.

Many Catholics in the region have been stepping up to help, converging on Notre Dame Parish in Kerrville, located in the hardest-hit community along the Guadalupe River.

KERRVILLE, Texas (AP) — Over the last decade, an array of Texas state and local agencies missed opportunities to fund a flood warning system intended to avert a disaster like the one that killed dozens of young campers and scores of others in Kerr County on the Fourth of July.