At least 82 people are dead and at least 41 more are missing after devastating flash floods slammed Texas Hill Country, with water rescues taking place along the Guadalupe River, which rose rapidly early Friday morning to the height of a two-story building.

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.

Catastrophic flooding struck central Texas on Friday as the Guadalupe River surged by more than 20 to 26 feet within 90 minutes, causing widespread devastation and forcing mass evacuations in Texas Hill Country. At least 80 people have been killed in the floods while others remain missing or displaced and more than 850 people required rescuing.