was described as "a slow-motion catastrophe" on , six days after slamming the Gulf Coast. Twenty years later, the storm is known as the costliest and one of to ever hit the United States.

Katrina first made landfall as a Category 1 storm in Florida on Aug. 25, 2005. It then intensified to a Category 5 hurricane in the Gulf. Weakening to a Category 3, it made landfall again on Aug. 29, 2005, in southeast Louisiana and then in Mississippi.

While the toll didn't become clear for days, the storm ultimately led to nearly 1,400 deaths, the majority in New Orleans, according to .

(A satellite image shows Hurricane Katrina as it approached the Gulf Coast in August 2005. Universal History Archive/Universal Images Group via Getty Images via CBS)

Initial reports suggested the damage in New Or

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