Over just two hours, the Guadalupe River at Comfort, Texas, rose from hip-height to three stories tall, sending water weighing as much as the Empire State building downstream roughly every minute it remained at its crest. The force of floodwater is often more powerful and surprising than people imagine.

Plans to develop a flood monitoring system in the Texas county hit hardest by deadly floods were scheduled to begin only a few weeks later.

Follow for live updates in the Texas flooding as the death toll rises to 120, as rescue operations start to shift to recovery phase

Well, it could take months for Texas families to experience some form of closure as more than 170 people remain missing, nearly a week after those deadly floodwaters rushed in the Texas Hill Country on July 4 as four months of rain fell in just two days over central Texas.

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."

The Houston Texans were the first to announce their donations on Saturday, July 5, with more coming throughout the week. The Dallas Cowboys and the NFL Foundation joined the Texans on Sunday, July 6, with each contributing $500,000 in a $1.5 million total donation.

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.

A retired nurse, her son, and a family friend say they were lucky to survive last week's flash floods in Texas that killed more than 100 people, including many summer campers.

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.

Ford Motor Co. and its philanthropic arm are donating money, and dealers will donate cars and other aid to Texans impacted by the flood.