Hurricane Katrina of the 2005 was the costliest natural disaster triggering one of the worst humanitarian disasters in the history of the United States. At least 1,836 people lost their lives in the actual hurricane and in the subsequent floods. The death toll was also attributable to a series of mismanagement of the flood rescue efforts.

Hurricane Katrina developed over the Bahamas on August 23, 2005 and crossed southern Florida as a moderate Category 1 hurricane before strengthening rapidly in the Gulf of Mexico. The storm made its landfall as a Category 3 storm on the morning of Monday, August 29 in southeast Louisiana. It caused severe destruction along the Gulf coast from central Florida to Texas, much of it due to the storm surge.

The most severe damage occurred in New Orleans, Louisiana as the levee system catastrophically failed to let floodwaters submerge 80% of the city. The worst property damage occurred in coastal areas, such as the Mississippi beachfront towns, which were flooded over 90% in hours, as boats and casino barges rammed buildings, pushing cars and houses inland, with waters reaching 6–12 miles (10–19 km) from the beach.