Hurricane Katrina
Hurricane Katrina was an extremely powerful and catastrophic tropical cyclone that killed 1,392 people and caused damage estimated at $125 billion, particularly in and around the city of New Orleans, in late August 2005. It is tied with Hurricane Harvey as being the costliest tropical cyclone in the Atlantic basin. Katrina was the twelfth tropical cyclone, the fifth hurricane, the third major hurricane, and the second Category 5 hurricane of the 2005 Atlantic hurricane season. It was also the fourth-most intense Atlantic hurricane to make landfall in the contiguous United States, as measured by barometric pressure.
Katrina formed on August 23, 2005, with the merger of a tropical wave and the remnants of a tropical depression. After briefly strengthening to a tropical storm over south Florida, Katrina entered the Gulf of Mexico on August 26 and rapidly intensified to a Category 5 hurricane before weakening to a Category 3 at its landfall on August 29 near Buras-Triumph, Louisiana.
Eighty percent of New Orleans, as well as large areas in neighboring parishes, were flooded. It is estimated that about 100,000 to 150,000 people remained in the City of New Orleans, despite mandatory evacuation orders. The flooding prompted a massive national and international response effort, including federal, local, and private rescue operations. The largest loss of life was due to flooding caused by engineering flaws in the federally built hurricane protection system, particularly the levees around New Orleans. Investigators concluded that the U.S. Army Corps of Engineers, tasked by Congress in the Flood Control Act of 1965 to design and build the region's hurricane protection, was responsible for the breached floodwalls. Later, a federal appeals court ruled that the Army Corps, despite being responsible, could not be held financially liable due to the Flood Control Act of 1928.
The emergency response from federal, state, and local governments was widely criticized, leading to the resignation of Federal Emergency Management Agency director Michael D. Brown and New Orleans Police Department superintendent Eddie Compass. Many other government officials faced criticism for their responses, especially New Orleans mayor Ray Nagin, Louisiana governor Kathleen Blanco, and President George W. Bush. However, several agencies, such as the United States Coast Guard, National Hurricane Center, and National Weather Service, were commended for their actions, with the NHC being particularly praised for its accurate forecasts well in advance.
The destruction and loss of life caused by the storm prompted the name Katrina to be retired by the World Meteorological Organization in April 2006. On January 4, 2023, the NHC updated the Katrina fatality data based on a 2014 report, which reduced the total number from an estimated 1,833 to 1,392.
Meteorological history
On August 19, 2005, a weak tropical wave combined with the mid-level remnants of Tropical Depression Ten and an upper tropospheric trough near the Lesser Antilles. On August 23, this disturbance organized into Tropical Depression Twelve over the southeastern Bahamas. The storm strengthened into Tropical Storm Katrina on the morning of August 24. The tropical storm moved towards Florida and became a hurricane only two hours before making landfall between Hallandale Beach and Aventura on the morning of August 25. The storm weakened over land, but it regained hurricane status about one hour after entering the Gulf of Mexico, and it continued strengthening over open waters. On August 27, the storm reached Category 3 intensity on the Saffir–Simpson hurricane wind scale, becoming the third major hurricane of the season. An eyewall replacement cycle disrupted the intensification but caused the storm to nearly double in size. Thereafter, Katrina rapidly intensified over the "unusually warm" waters of the Loop Current, from a Category 3 hurricane to a Category 5 hurricane in just nine hours.After attaining Category 5 hurricane status on the morning of August 28, Katrina reached its peak strength at 1800 UTC, with maximum sustained winds of and a minimum central pressure of. The pressure measurement made Katrina the fifth most intense Atlantic hurricane on record at the time, only to be surpassed by Hurricanes Rita and Wilma later in the season; it was also the strongest hurricane ever recorded in the Gulf of Mexico at the time, before Rita broke the record. The hurricane subsequently weakened due to another eyewall replacement cycle, and Katrina made its second landfall at 1110 UTC on August 29, as a high-end Category 3 hurricane with sustained winds of, near Buras-Triumph, Louisiana. At landfall, hurricane-force winds extended outward from the center and the storm's central pressure was. After moving over southeastern Louisiana and then Breton Sound, it made its third and final landfall near the Louisiana–Mississippi border, with Category 3 sustained winds of. Katrina maintained hurricane strength well into Mississippi, finally weakening to tropical storm strength more than inland near Meridian, Mississippi. It was downgraded to a tropical depression near Clarksville, Tennessee; its remnants were absorbed by a cold front in the eastern Great Lakes region on August 31. The resulting extratropical storm moved rapidly to the northeast and affected eastern Canada before finally dissipating off the eastern coast of Greenland on September 7.
Preparations
Federal government
The United States Coast Guard began pre-positioning resources in a ring around the expected impact zone and activated more than 400 reservists. On August 27, it moved its personnel out of the New Orleans region prior to the mandatory evacuation. Aircrews from the Aviation Training Center, in Mobile, staged rescue aircraft from Texas to Florida. All aircraft were returning towards the Gulf of Mexico by the afternoon of August 29. Aircrews, many of whom lost their homes during the hurricane, began a round-the-clock rescue effort in New Orleans, and along the Mississippi and Alabama coastlines.President George W. Bush declared a state of emergency in selected regions of Louisiana, Alabama, and Mississippi on August 27. "On Sunday, August 28, President Bush spoke with Governor Blanco to encourage her to order a mandatory evacuation of New Orleans." However, during the testimony by former Federal Emergency Management Agency chief Michael Brown before a U.S. House subcommittee on September 26, Representative Stephen Buyer inquired as to why Bush's declaration of state of emergency of August 27 had not included the coastal parishes of Orleans, Jefferson, and Plaquemines. The declaration actually did not include any of Louisiana's coastal parishes, whereas the coastal counties were included in the declarations for Mississippi and Alabama. Brown testified that this was because Louisiana Governor Blanco had not included those parishes in her initial request for aid, a decision that he found "shocking". After the hearing, Blanco released a copy of her letter, which showed she had requested assistance for "all the southeastern parishes including the City of New Orleans" as well as specifically named 14 parishes, including Jefferson, Orleans, St. Bernard, and Plaquemines.
Voluntary and mandatory evacuations were issued for large areas of southeast Louisiana as well as coastal Mississippi and Alabama. About 1.2 million residents of the Gulf Coast were covered under a voluntary or mandatory evacuation order.
National Oceanic and Atmospheric Administration (NOAA)
On the afternoon of August 26, the National Hurricane Center realized that Katrina had yet to make the turn toward the Florida Panhandle and ended up revising the predicted track of the storm from the panhandle to the Mississippi coast. The National Weather Service's New Orleans/Baton Rouge office issued a vividly worded bulletin on August 28 predicting that the area would be "uninhabitable for weeks" after "devastating damage" caused by Katrina, which at that time rivaled the intensity of Hurricane Camille. During video conferences involving the president later that day and on August 29, NHC director Max Mayfield expressed concern that Katrina might push its storm surge over the city's levees and flood walls. In one conference, he stated, "I do not think anyone can tell you with confidence right now whether the levees will be topped or not, but that's obviously a very, very great concern."Gulf Coast
Florida
In Florida, Governor Jeb Bush declared a state of emergency on August 24 in advance of Hurricane Katrina's landfall. By the following day, Florida's Emergency Operations Center was activated in Tallahassee to monitor the progress of the hurricane. Before Katrina moved ashore, schools and businesses were closed in the Miami area. Cruise ships altered their paths due to seaports in southeastern Florida closing. Officials in Miami-Dade County advised residents in mobile homes or with special needs to evacuate. To the north in Broward County, residents east of the Intracoastal Waterway or in mobile homes were advised to leave their homes. Evacuation orders were issued for offshore islands in Palm Beach County, and for residents in mobile homes south of Lantana Road. Additionally, a mandatory evacuation was ordered for vulnerable housing in Martin County. Shelters were opened across the region. Officials closed the Miami International Airport, Fort Lauderdale–Hollywood International Airport, Key West International Airport, and Florida Keys Marathon Airport due to the storm. In Monroe and Collier counties, schools were closed, and a shelter was opened in Immokalee.Alabama
On August 28, Alabama Governor Bob Riley declared a state of emergency for the approaching Hurricane Katrina. On the same day, he requested President Bush to declare "expedited major disaster declaration" for six counties of South Alabama, which was quickly approved. Three hundred fifty national guardsmen were called on duty by August 30. The state of Mississippi activated its National Guard on August 26 in preparation for the storm's landfall. Additionally, the state government activated its Emergency Operations Center the next day, and local governments began issuing evacuation orders. By 6:00 p.m. CDT on August 28, 11 counties and cities issued evacuation orders, a number which increased to 41 counties and 61 cities by the following morning. Moreover, 57 emergency shelters were established on coastal communities, with 31 additional shelters available to open if needed.By Sunday, August 28, most infrastructure along the Gulf Coast had been shut down, including all freight and Amtrak rail traffic into the evacuation areas as well as the Waterford Nuclear Generating Station. Since Hurricane Katrina, Amtrak's Sunset Limited service has never been restored past New Orleans.