With more than 170 still missing, communities must reconcile how to pick up the pieces around a waterway that remains both a wellspring and a looming menace.

The Guadalupe River has a history of deadly flooding. Here is a look over the decades. (AP video Marshall Ritzel/Albee Zhang)

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.

At least 110 people are dead and dozens are still missing after devastating flash floods slammed Texas Hill Country, with water rescues taking place along the Guadalupe River, which rose rapidly early Friday morning to the height of a two-story building.

Devastating flash floods in Central Texas on Friday have killed more than 100 people, including over two dozen at Camp Mystic, a Christian summer camp for girls along the Guadalupe River.  More than 160 people remain unaccounted for,