The devastating aftermath of Hurricane Katrina exposed a series of deep-rooted problems, including controversies over the federal government's response, difficulties in search-and-rescue efforts, and lack of preparedness for the storm, particularly with regard to the city's aging series of levees—50 of which failed during the storm, significantly flooding the low-lying city and causing much of the damage.

The U.S. Army Corps of Engineers pumped the last of the floodwaters out of the city on October 11, 2005, some 43 days after Katrina made landfall. Ultimately, the storm caused more than $160 billion in damage, and the population of New Orleans fell by 29 percent between the fall of 2005 and 2011.