The term 'Catastrophic New Orleans Hurricane' refers to Hurricane Katrina, which struck the Gulf Coast of the United States in August 2005. It was one of the most destructive and costliest hurricanes in US history, causing over 1, 800 deaths and an estimated $108 billion in damage. The storm caused catastrophic flooding in New Orleans, Louisiana, where levees and flood walls failed, leading to the displacement of hundreds of thousands of people.