Hurricane preparedness for New Orleans two months later. Hurricane Katrina threatened the city in August 2005. The eye of the huge storm grazed the eastern side of the city, sparing it from the worst of its power. However, due to poorly designed levees and the worst civil engineering failure in United States history, most of the city experienced flooding similar to a direct hit; see: Levee failures in Greater New Orleans, 2005. There were many predictions of hurricane risk in New Orleans before Katrina. On August 26 the storm, at one point up to a Category 5, was in the Gulf with a projection to
Hurricane preparedness for New Orleans Hurricane Ivan's threat to the city resulted in the largest evacuation of the city to date. Mayor Ray Nagin issued a call for a voluntary evacuation of the city at 6 pm on September 13. An estimated 600,000 or more evacuated from Greater New Orleans. The contraflow plan was put into full effect for the first time, but rather late in the evacuation due to various confusions. This proved valuable practice, for the contraflow was implemented much more smoothly in 2005. Hurricane Pam was a hypothetical hurricane used as a disaster scenario to drive planning for a 13-parish area in