Thirteen people have died after heavy rain pounded Kerr County, Texas, early Friday, leading to "catastrophic" flooding, the sheriff said.

Twenty children at Camp Mystic are not accounted for, Acting Governor Dan Patrick said in a news conference on Friday.

The area is home to many summer camps, and Texas Lt. Gov. Dan Patrick said at least 20 girls are missing from Camp Mystic. He said families whose daughters are unaccounted for have been notified; parents who have not been contacted by the camp should know their daughters are safe, he stressed.