Flash flood alley is a curved-shaped region about 300 miles long and 50 miles wide in central/south-central Texas, extending from north of Dallas to southwest of San Antonio. Its location, weather patterns, and geology often combine to create devastating floods.

Flash floods happen when heavy rains unleash more water than the ground can absorb, causing that water to pile up and flow to low-lying areas

Kerrville, Texas was hit especially hard by flash flooding after heavy rain swelled two forks of the Guadalupe River, according to officials. Residents told CNN affiliate KSAT how the flood caught them by surprise and destroyed their homes.