Hurricane Katrina was the deadliest and most destructive Atlantic tropical cyclone of the 2005 Atlantic hurricane season. It was the costliest natural disaster, as well as one of the five deadliest hurricanes, in the history of the United States. Among recorded Atlantic hurricanes, it was the sixth strongest overall. At least 1,833 people died in the hurricane and subsequent floods, making it the deadliest U.S. hurricane since the 1928 Okeechobee hurricane; total property damage was estimated at $81 billion (2005 USD), nearly triple the damage brought by Hurricane Andrew in 1992.
Hurricane Katrina formed over the Bahamas on August 23, 2005 and crossed southern Florida as a moderate Category 1 hurricane, causing some deaths and flooding there before strengthening rapidly in the Gulf of Mexico. The hurricane strengthened to a Category 5 hurricane over the warm Gulf water, but weakened before making its second landfall as a Category 3 hurricane on the morning of Monday, August 29 in southeast Louisiana. It caused severe destruction along the Gulf coast from central Florida to Texas, much of it due to the storm surge. The most significant number of deaths occurred in New Orleans, Louisiana, which flooded as the levee system catastrophically failed, in many cases hours after the storm had moved inland. Eventually 80% of the city and large tracts of neighboring parishes became flooded, and the floodwaters lingered for weeks. However, the worst property damage occurred in coastal areas, such as all Mississippi beachfront towns, which were flooded over 90% in hours, as boats and casino barges rammed buildings, pushing cars and houses inland, with waters reaching 6–12 miles (10–19 km) from the beach.
The French Quarter, also known as the Vieux Carré, is the oldest neighborhood in the city of New Orleans. When New Orleans (La Nouvelle-Orléans in French) was founded in 1718 by Jean-Baptiste Le Moyne de Bienville, the city was originally centered on the French Quarter, or the Vieux Carré ("Old Square" in French) as it was known then. While the area is still referred to as the Vieux Carré by some, it is more commonly known as the French Quarter today, or simply "The Quarter." Although called the "French" Quarter, most of the present day buildings were built under Spanish rule and show Spanish colonial tastes. The district as a whole is a National Historic Landmark, and contains numerous individual historic buildings. It was affected relatively lightly by Hurricane Katrina in 2005, as compared to other areas of the city and the greater region.
The French Quarter is located atand has an elevation of 3 feet (0.9 m). According to the United States Census Bureau, the district has a total area of 0.66 square miles (1.7 km2). 0.49 square miles (1.3 km2) of which is land and 0.17 square miles (0.4 km2) (25.76%) of which is water.
As the center of Hurricane Katrina passed southeast of New Orleans on August 29, 2005, winds downtown were in the Category 3 range with frequent intense gusts and tidal surge. Hurricane-force winds were experienced throughout the city, although the most severe portion of Katrina missed the city, hitting nearby St. Bernard and Plaquemines parishes. Hurricane Katrina made its final landfall in eastern St. Tammany Parish. The western eye wall passed directly over St. Tammany Parish, Louisiana as a Category 3 hurricane at about 9:45 am CST, August 29, 2005. The communities of Slidell, Louisiana, Avery Estates, Lakeshore Estates, Oak Harbor, Eden Isles and Northshore Beach were inundated by the storm surge that extended over six miles inland. The storm surge affected all 57 miles (92 km) of St. Tammany Parish’s coastline, including Lacombe, Mandeville and Madisonville. The storm surge in the area of the Rigolets Pass was estimated to be 16 feet, not including wave action, declining to 7 feet (2.1 m) at Madisonville. The surge had a second peak in eastern St. Tammany as the westerly winds from the southern eye wall pushed the surge to the east, backing up at the bottleneck of the Rigolets Pass.
In the City of New Orleans, the storm surge caused more than 50 breaches in drainage canal levees and also in navigational canal levees and precipitated the worst engineering disaster in the history of the United States. By August 31, 2005, 80% of New Orleans was flooded, with some parts under 15 feet (4.6 m) of water. The famous French Quarter dodged the massive flooding experienced in other levee areas. Most of the city's levees designed and built by the United States Army Corps of Engineers broke somewhere, including the 17th Street Canal levee, the Industrial Canal levee, and the London Avenue Canal floodwall. These breaches were responsible for most of the flooding, according to a June 2007 report by the American Society of Civil Engineers. Oil refining was stopped in the area, increasing oil prices worldwide.
Drainage in New Orleans, Louisiana has been a major concern since the founding of the city in the early 18th century, remaining an important factor in the history of New Orleans today. The central portion of metropolitan New Orleans (New Orleans/Metairie/Kenner) is fairly unique in that it is almost completely surrounded by water: Lake Pontchartrain to the north, Lake Borgne to the east, wetlands to the east and west, and the Mississippi River to the south. Much of the land area between these bodies of water is at or below sea level, and no longer has a natural outlet for flowing surface water. As such, virtually all rainfall occurring within this area must be removed through either evapotranspiration or pumping. Thus, flood threats to metropolitan New Orleans include the Mississippi River, Lake Pontchartrain, and natural rainfall. Artificial levees have been built to keep out rising river and lake waters but have had the negative effect of keeping rainfall in.
New Orleans was originally built on natural levees along the Mississippi River that were a result of soil deposits left from the river's annual floods. The site chosen for New Orleans had many advantages. Because it sits where distance between the river and Lake Pontchartrain is shortest, Louisiana Indians had long used the area as a depot and market for goods carried between the two waterways. The narrow strip of land also aided rapid troop movements, and the river's crescent shape slowed ships approaching from downriver and exposed them to gunfire, however flooding was always a hazard.
The Atlantic hurricane season is the period in a year when hurricanes usually form in the Atlantic Ocean. Tropical cyclones in the North Atlantic are called hurricanes, tropical storms, or tropical depressions. In addition, there have been several storms over the years that have not been fully tropical which are categorised as subtropical depressions and subtropical storms.
Worldwide, tropical cyclone activity peaks in late summer, when the difference between temperatures aloft and sea surface temperatures is the greatest. However, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month, while September is the most active. In the Northern Atlantic Ocean, a distinct hurricane season occurs from June 1 to November 30, sharply peaking from late August through September; the season's climatological peak of activity occurs around September 10 each season.