New Orleans 1980s and 1990s, scientists observed that extensive, rapid, and ongoing erosion of the marshlands and swamp surrounding New Orleans, especially that related to the Mississippi River – Gulf Outlet Canal, had the unintended result of leaving the city more vulnerable than before to hurricane-induced catastrophic storm surges. New Orleans was catastrophically affected by what Raymond B. Seed called "the worst engineering disaster in the world since Chernobyl", when the Federal levee system failed during Hurricane Katrina in 2005. By the time the hurricane approached the city at the end of August 2005, most residents had evacuated. As the hurricane passed
1915 New Orleans hurricane seas produced by the hurricane along the Louisiana coast arrived shortly before the storm made landfall. Evacuees departing the coast as late as September 28 reported no abnormal tides along the shore. However, sea levels began to rise at abnormally rapid rates on the morning of September 29 as the hurricane neared. By the afternoon hours, low-lying lands south of New Orleans and east towards Bay St. Louis, Mississippi, as well as areas adjacent to Lake Pontchartrain, were inundated by the quickly rising storm surge. Levee overtopping along Lake Pontchartrain resulted in the flooding of much of western New Orleans.