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."

On the night the deadly floodwaters raged down the Guadalupe River in Texas, the National Weather Service forecast office in Austin/San Antonio was missing a key member of its team: the warning coordination meteorologist,

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.

The family had little time to think of a way out. They started using lobster buoys and a pocketknife to make a hole in the sleeping loft to escape.

More than two dozen Mexican rescue volunteers and firefighters have been looking for victims and clearing debris along the Guadalupe River. Others were left waiting for visas and humanitarian permits to cross the border.

Here's what to know about the deadly flooding, the colossal weather system that drove it and ongoing efforts to identify victims.

At least 87 people are dead after heavy rain led to devastating flooding in Texas. Kerr County was hit the hardest, with at least 75 deaths, including 27 children. President Donald Trump signed a disaster declaration for the county and the Federal Emergency Management Agency is on the ground there.

After hearing a young woman scream for her life on the flooded Guadalupe River, Carl Jeter called first responders to rescue her after she tread water for 15 miles.