More Than 20,000 Rescued, 6 Dead From Catastrophic Louisiana Floods; Federal Emergency Declared

— -- More than 20,000 Louisiana residents have been rescued from their homes, and 12,000 are in shelters in the wake of historic, devastating flash flooding that led President Barack Obama on Sunday evening to declare a federal emergency in the state, authorities said. At least six people have died in the disaster.

Gov. John Bel Edwards said that 40,000 businesses and homes are without power and that rescue workers are still "bringing people out of homes to safety," particularly in the hardest-hit areas around Baton Rouge. More than 500 pets have also been rescued, according to authorities.

Curfews for several areas in the state were issued again overnight Sunday as emergency crews try to get a grasp on the situation, said ABC News meteorologist Dan Manzo.

Louisiana Residents Clean Up After Catastrophic Flood

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President Barack Obama and Louisiana Senators David Vitter and Bill Cassidy, tour a flood-affected neighborhood in Zachary, Louisiana, Aug. 23, 2016.

Jonathan Ernst/Reuters

More than 30 inches of rain fell in southern Louisiana over the past week, causing waterways to surge, Manzo said. The biggest amount was in Watson, which was deluged with 31.4 inches of rain, according to the National Weather Service.

The state has had "historic levels of rivers rising," Edwards told ABC News' "Good Morning America," adding that he is "worried like everyone else" and "trying to let the nation know."

Louisiana has long been extremely vulnerable to flooding because of rising sea levels and the state's low-lying land. The catastrophe over the past few days showed the damage and loss that that can result.