Hurricane Katrina

Hurricane Katrina was one of the most destructive tropical cyclones ever to hit the United States. It caused extensive damage to the coastal regions of Louisiana, Mississippi, and Alabama on August 29, 2005. By late morning of August 29, the storm caused several sections of the levee system in New Orleans, Louisiana to collapse. Subsequent flooding over most of the city, a large part of which lies below sea level, resulted in widespread damage and many deaths, largely due to inadequate hurricane preparedness for New Orleans.

Later estimates placed the death toll in the thousands, and the damage is expected to surpass Hurricane Andrew as the costliest natural disaster in U.S. history (estimates run as high as $100 billion). Over a million people were displaced — a humanitarian crisis on a scale unseen in the U.S. since the Great Depression.

Federal disaster declarations blanketed 90,000 square miles (233,000 km²) of the United States, an area almost as large as the United Kingdom. The hurricane left an estimated five million people without power, and it may take up to two months for all power to be restored. On September 3, Homeland Security Secretary Michael Chertoff described the aftermath of Hurricane Katrina as "probably the worst catastrophe, or set of catastrophes" in the country's history, referring to the hurricane itself plus the flooding of New Orleans.