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 part of Texas is one of the most flood-prone areas in the entire world. Here’s a look at some of the region’s worst floods on record.

More than 100 deaths have been reported statewide, with most near the Guadalupe River. Several girls from the Dallas area are among the deaths confirmed from Camp Mystic.