Hurricane Katrina

The tropical depression that became Hurricane Katrina formed over the Bahamas on August 23, 2005, and meteorologists were soon able to warn people in the Gulf Coast states that a major storm was on its way. The following day, Florida Governor Jeb Bush declared a state of emergency, activating the state's Emergency Operations Center in Tallahassee.

By August 28, voluntary evacuations were underway across the entire Gulf Coast region, and the National Weather Service issued an alarming all-caps weather alert that predicted the level of damage in graphic detail:

"MOST OF THE AREA WILL BE UNINHABITABLE FOR WEEKS ... PERHAPS LONGER. AT LEAST ONE HALF OF WELL CONSTRUCTED HOMES WILL HAVE ROOF AND WALL FAILURE ... LEAVING THOSE HOMES SEVERELY DAMAGED OR DESTROYED.

HIGH RISE OFFICE AND APARTMENT BUILDINGS WILL SWAY DANGEROUSLY ... A FEW TO THE POINT OF TOTAL COLLAPSE. ALL WINDOWS WILL BLOW OUT.

AIRBORNE DEBRIS WILL BE WIDESPREAD ... PERSONS ... PETS ... AND LIVESTOCK EXPOSED TO THE WINDS WILL FACE CERTAIN DEATH IF STRUCK."

New Orleans, a city of more than 484,000 residents, was at particular risk. Though about half the city lies above sea level, its average elevation is about six feet below sea level–and with Lake Pontchartrain to the north, the Gulf of Mexico to the southeast and the Mississippi River running right through it, New Orleans is almost completely surrounded by water.

Over the course of the 20th century, the Army Corps of Engineers had built a complex system of levees and seawalls to keep New Orleans from flooding. The levees along the Mississippi were strong and sturdy, but the ones built to hold back Lake Pontchartrain, Lake Borgne and the bayous and wetlands to the city’s east and west were much less reliable.

Before the hurricane hit, officials worried that a storm surge could overflow some levees and cause short-term flooding, but no one predicted levees might collapse. Neighborhoods that sat below sea level, many of which housed the city’s poorest and most vulnerable people, were at the greatest risk of catastrophic flooding.

The day before Katrina hit, New Orleans Mayor Ray Nagin issued the city’s first-ever mandatory evacuation order. By nightfall, almost 80 percent of the city’s population had evacuated. However, some 112,000 city residents did not have access to a car or any other way of evacuating.

Nagin also declared that the Superdome, a stadium located on relatively high ground near downtown and home of the New Orleans Saints NFL team, would serve as one of several “shelters of last resort” for people who could not leave the city. Before Katrina hit, some 10,000 residents sought shelter in the Superdome or other shelters, while tens of thousands of others chose to ride out the storm at home.

Early in the morning on Monday, August 29, Hurricane Katrina made landfall, striking Louisiana, Mississippi and Alabama as a Category 3 storm on the Saffir-Simpson Hurricane Scale, with maximum sustained winds of about 125 mph and some 15 inches of rainfall.

But the most severe damage occurred after the hurricane, when the storm surge (at least 20 feet in some places) overwhelmed many of the city’s unstable levees and drainage canals. Water seeped through the soil underneath some levees and swept others away entirely.

By 9 a.m., low-lying places like St. Bernard Parish and the Ninth Ward were under so much water that people had to scramble to attics and rooftops for safety. Eventually, roughly 80 percent of New Orleans was under some level of water. The American Society of Civil Engineers called the failure of flood control in the New Orleans area “the worst engineering catastrophe in U.S. history."

Many people acted heroically in the aftermath of Hurricane Katrina. The Coast Guard rescued some 34,000 people in New Orleans alone, and many ordinary citizens commandeered boats, offered food and shelter, and did whatever else they could to help their neighbors. Yet the government–particularly the federal government–seemed wholly unprepared for the disaster. The Federal Emergency Management Agency (FEMA) took days to establish operations in New Orleans, and even then did not have a coordinated plan of action.

Officials including President George W. Bush, seemed unaware of just how bad things were in New Orleans and elsewhere: how many people were stranded or missing; how many homes and businesses had been damaged; or how much food, water and aid was needed. Katrina had left in her wake what one reporter called a “total disaster zone” where people were “getting absolutely desperate.”

Many residents of New Orleans–with their homes beneath floodwaters–had nowhere to go. At the Superdome, where supplies were limited to begin with, officials accepted 15,000 more refugees from the storm on Monday before locking the doors. Tens of thousands of people desperate for food, water and shelter broke into the Ernest N. Morial Convention Center complex, where they found nothing but chaos.

Meanwhile, it was nearly impossible to leave New Orleans: People without cars or anyplace to go were stuck. Some people, for example, tried to walk over the Crescent City Connection bridge to the nearby suburb of Gretna, but armed police officers forced them to turn back.

Katrina also pummeled huge areas of Louisiana, Mississippi and Alabama, but the desperation was most concentrated in New Orleans. Before the storm, the city’s population was mostly black (about 67 percent); moreover, nearly 30 percent of its people lived in poverty. Katrina exacerbated these conditions and left many of New Orleans’s poorest citizens even more vulnerable than they had been before the storm.

Estimates vary, but Hurricane Katrina is believed to have caused between 1,200 and 2,000 deaths, including indirect deaths such as shootings, suicides, drug overdoses and gas-poisoning deaths. Days after the hurricane struck, bodies were still being recovered from inside flooded buildings and pockets of floodwaters.

Some deaths–which may have been preventable–resulted in years-long investigations, such as the deaths of 215 sick and elderly patients at hospitals and long-term care facilities in southern Louisiana.

Katrina and its high winds and rainfall affected some 90,000 square miles of the United States, from the Gulf Coast to the Great Lakes. Hundreds of thousands of evacuees scattered far and wide, often settling in cities like Houston, San Antonio, Baton Rogue and Atlanta. According to The Data Center, an independent research organization in New Orleans, the storm ultimately displaced more than 1 million people in the Gulf Coast region.

The population of New Orleans plummeted in the aftermath of Katrina: By 2006 it had fallen to a low of about 230,000 people–less than half of its pre-Katrina population. It has since rebounded to about 386,000 residents, but the Crescent City remains short of its previous population level.

In the wake of the storm's devastating effects, local, state and federal governments were criticized for their slow, inadequate response, as well as for the levee failures around New Orleans. And officials from different branches of government were quick to direct the blame at each other.

"We wanted soldiers, helicopters, food and water," Denise Bottcher, press secretary for Governor Kathleen Blanco of Louisiana told the New York Times. "They wanted to negotiate an organizational chart."

Mayor Nagin argued that there was no clear designation of who was in charge, telling reporters, “The state and federal government are doing a two-step dance."

President Bush originally praised his director of FEMA, Michael D. Brown, infamously declaring "Brownie, you're doing a heck of a job." But as criticism mounted and glaring inadequacies were exposed, Brown was forced to resign, as was the New Orleans Police Department Superintendent.

Governor Blanco declined to seek re-election in 2007 and Mayor Nagin left office in 2010. In 2014 Nagin was convicted of bribery, fraud and money laundering while in office.

The U.S. Congress launched an investigation into the government response to the storm and issued a highly critical report in February 2006 titled, "A Failure of Initiative: Final Report of the Select Bipartisan Committee to Investigate the Preparation for and Response to Hurricane Katrina." Among the report's findings:

The dismal failures in preparation for Katrina, and in the response during and after the disaster, spurred a series of reforms initiated by Congress. Chief among them was a requirement that all levels of government train to execute coordinated plans of disaster response. In the decade following Katrina, FEMA paid out billions in grants to ensure better preparedness.

Meanwhile, the Army Corps of Engineers built an improved, $14 billion network of levees and floodwalls around New Orleans. The agency said the work ensured the city's safety from flooding for the time being. But the Army Corps also stated that, in the face of a changing climate, rising sea levels and the loss of protective barrier islands, the system will fall short of providing long-term protection without significant routine upgrades.

Officials Urge Preparedness As Katrina Intensifies. FEMA. National Weather Service: New Orleans, LA. The Most Expensive Natural Disasters in US History. Kiplinger. NASA On Air: NASA Compares Katrina And Sandy Wind Fields (8/24/2015). NASA. Extremely Powerful Hurricane Katrina Leaves a Historic Mark on the Northern Gulf Coast. National Weather Service. Hurricane Katrina. LSU. Lake Pontchartrain and Vicinity (LPV) Project Future Levee Lifts. Army Corps of Engineers.