1900 Galveston hurricane
The Great Galveston hurricane made landfall on September 9, 1900, near Galveston, Texas. It had estimated winds of at landfall, making the cyclone a Category 4 storm on the modern day Saffir–Simpson Hurricane Scale.
The hurricane caused great loss of life, with a death toll of between 6,000 and 12,000 people; the number most cited in official reports is 8,000, giving the storm the third-highest number of deaths or injuries of all Atlantic hurricanes, after the Great Hurricane of 1780 and Hurricane Mitch in 1998. The Galveston Hurricane of 1900 is the deadliest natural disaster to strike the United States. This loss of life can be attributed to the fact that officials for the Weather Bureau in Galveston brushed off the reports because the city had "weathered them all" and they did not realize the threat. The second-deadliest storm to strike the United States, the San Ciriaco hurricane of 1899, caused around 3,400 deaths.
New Orleans
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 through the Gulf Coast region, the city's federal flood protection system failed, resulting in the worst civil engineering disaster in American history. Floodwalls and levees constructed by the United States Army Corps of Engineers failed below design specifications and 80% of the city flooded. Tens of thousands of residents who had remained were rescued or otherwise made their way to shelters of last resort at the Louisiana Superdome or the New Orleans Morial Convention Center. More than 1,500 people were recorded as having died in Louisiana, most in New Orleans, while others remain unaccounted for. Before Hurricane Katrina, the city called for the first mandatory evacuation in its history, to be followed by another mandatory evacuation three years later with Hurricane Gustav.