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.

More than 100 people have been confirmed dead since July 4, when the Guadalupe River in central Texas swelled overnight and triggered flash floods that swept through an area known locally as “Flash Flood Alley.

More than 100 people have died and dozens of others are missing following devastating central Texas floods that tore through local communities along the Guadalupe River early Friday. Fast-moving waters rose some 26 feet in under an hour overnight,