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.

Over 100 people have died after heavy rain pounded Kerr County, Texas, early Friday, leading to "catastrophic" flooding, the sheriff said.

Satellite imagery of Camp Mystic and other areas along the Guadalupe River shows the devastating aftermath of the Fourth of July floods in Texas.

Items from inside a cabin sit on the ground at Camp Mystic, in the aftermath of deadly flooding in Kerr County. At least 95 people have died in Kerr County, Texas, according to officials, after devastating flash floods swept through south central Texas on Friday,