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

This part of Texas Hill Country is known for flash floods. Why were so many people caught off guard when the river turned violent?

Torrential rain flooded creeks, streams and the Guadalupe River, where the water swelled more than 26 feet in 45 minutes.

Eight-year-old girls at sleep-away camp, families crammed into recreational vehicles, local residents traveling to or from work. These are some of the victims.

Americans are heartbroken, says Pastor Jesse Bradley of Grace Community Church in the Seattle area, over the tragic flooding and deaths in Texas. He urges prayer, strength and closeness to God for all those affected as recovery efforts continue.

Katherine Ferruzzo had been accepted to the University of Texas at Austin for the fall semester and planned to become a Special Education teacher, her family said.

Jeff Ramsey also called his mother and his brother-in-law, who were staying in a cabin nearby and were able to escape.

In the Midwest, quarter-sized hail and an isolated tornado cannot be ruled out, while in the South, flood alerts are in effect for areas that were devastated by flash floods last week.

According to the National Weather Service, Vermont's experience with floods can be traced to both ongoing climate change and the state's mountainous geography.

Texas, joins 'Fox News Sunday' to discuss his experience walking President Donald Trump around the destruction caused by floods in Kerr County, Texas.