Hurricane Katrina directly affected five American states between August 25 and August 29, 2005. It was one of the strongest hurricanes to reach landfall in the United States in the past one hundred years.


Hurricane Katrina was one of the costliest natural disasters in U.S. history. The hurricane and resultant flooding are believed to have caused $81 billion in damages and $41 billion in insurance claims. Over 275,000 homes were destroyed and more than 1,800 people were killed. Although the hurricane affected five states and the related flooding affected two more, the most seriously affected states were Louisiana, Mississippi, and Alabama. The most damaged city was New Orleans, 80% of which was under water.

Risk factors

Tropical storms and hurricanes are not uncommon in the Atlantic and Gulf Coast regions. Between 1995 and 2005, the number of tropical storms in this area was above normal. Whereas between 1970 and 1995, an average of 8.6 named storms occurred annually, between 1995 and 2005 an average of 13 named storms developed. Additionally, during these ten years, an average of 7.7 hurricanes and 3.6 major hurricanes developed in the Atlantic basin, compared to an average of 5.0 hurricanes and 1.5 major hurricanes each year between 1970 and 1995. Studies show that during the period during which the strength and destructiveness of hurricanes increased there was a rapid increase in global land and ocean temperatures.

New Orleans had specific risk factors that magnified the devastation experienced by Katrina. Hurricanes are not uncommon in the Gulf Coast, which led some New Orleans residents to be optimistic and not respond to requests to evacuate before the storm. Also, New Orleans had a poverty rate of 23%, and 27% of households in the city did not own a car, making evacuation more difficult for these people.

City and governmental factors also played a role in the destruction of New Orleans and other Gulf Coast cities. Many believe that authorities were not clear enough in their warnings to evacuate. They have been accused of treating Katrina as a routine natural disaster, being slow to call for evacuations, and failing to elicit the needed response from all residents to leave the city. Beyond this, a shortage of social networks and programs to help the evacuation process made leaving the city difficult for the poor and the elderly and disabled.

The infrastructure of the levees built to protect New Orleans also played a major role in the mass flooding of the city. Although the Federal Emergency Management Agency (FEMA) ranked the potential disaster in New Orleans as critical, preparation was later thought to have been inadequate. The manmade levees protecting the city were built under sea level and were not strong enough to withstand the pressure from the rising water. Plus, most of New Orleans is below sea level and is built on sand, silt, and clay, which has caused the city to sink at a rate of 0.15 to 0.2 inches (0.38 to 0.5 cm) a year. These factors conspired to make Katrina and the associated flooding one of the worst natural disasters ever to strike the United States.


Hurricane Katrina, August 29th, 2005.

Hurricane Katrina, August 29th, 2005.
(NOAA/Science Source)

Before Katrina, over 480,000 people lived within the city limits of New Orleans in over 215,000 housing units. In total, there were over 1.3 million people living in the New Orleans metropolitan area. New Orleans had a high school graduation rate of 68% and 22% of residents had a bachelor's degree. Unemployment before the hurricane was at 12%, twice the national average at that time, and unemployment for African American workers was 20% higher in New Orleans than for black workers in the rest of the United States. Two-thirds of the population in New Orleans was black, and 23% of the population was considered to be living in poverty. Those who were employed often held low-wage jobs. The average hourly pay rate in New Orleans in 2004, was $16.76, about 7% below the national hourly wage average. Poverty and lack of transportation were later seen as major factors in causing residents to stay behind with their belongings and not evacuate as requested.

Development and impact

First, Katrina was a tropical depression located in the southeastern Bahamas. This tropical depression strengthened and received the name tropical storm Katrina on August 24, 2005. The next day the tropical storm strengthened to a category 1 hurricane a few hours before it hit landfall in Florida at 6:30 EDT on August 25. Hurricane Katrina spent seven hours over Florida, dropping up to 15 inches (38 cm) of rain in some areas, causing flooding and a loss of power to 1.3 million. Fourteen people died in Florida because of the storm.

Next Katrina returned to the Gulf of Mexico and headed west toward Texas. Over warm Gulf water, it strengthened, and on August 26, it was classified as a major hurricane. Its path curved northward as it continued to build. On August 28, it reached maximum wind speeds of 170 mph (150 kts [nautical miles per hour]) and was classified as a category 5 hurricane. Katrina reached landfall on the morning of August 29, as a category 3 hurricane with wind speeds as high as 125 mph (110 kts).

Common diseases and disorders

For those in regions directly affected by the hurricane, immediate injuries included sprains, breaks, and lacerations. Shortly after the hurricane, common treatments sought were for skin infections and rashes, gastrointestinal problems, acute respiratory illness, and needed tetanus shots. Dehydration, heat exhaustion, and heat stroke were also experienced. Ongoing after the initial disaster, mental illness was a major concern of health officials. Need for prescription refills and treatments for people with ongoing medical conditions was also a pervasive problem.

Although initially there was fear of typhoid, cholera, and West Nile virus spreading, the affected areas did not experience these outcomes. There were five cases of reported West Nile virus, ten in the three weeks after the hurricane; however, Louisiana had already had over 52 reported cases in 2005.


Many hospitals and clinics were prepared to handle the emergency. However, hospitals and clinics hit directly were damaged or destroyed. Many patients were relocated to nearby states, such as Texas, to receive treatment. Additionally, medical supplies were brought into the affected area by emergency teams and organizations.

A larger problem facing survivors was the limited food, water, and shelter. Over 15,000 people were housed in the Louisiana Superdome; 20,000 in the Ernest N. Morial Convention Center; and 13,000 in the Reliant Astrodome in Houston. Other shelters opened to evacuees but found that they were filled beyond capacity within hours. Transportation to more distant states with space was often costly, difficult to organize, and sometimes separated family members.

The Center for Disease Control (CDC) and Louisiana officials began a mosquito-control program by September 1, in order to control the possible spread of West Niles virus. Temporary housing and up to 18 months of rental assistance was offered by FEMA for families who lost their homes or had homes that were uninhabitable. Additionally, crisis counseling was offered both immediately after the hurricane and over the following months for those experiencing posttraumatic stress, mental illness, or depression.

Public role and response

Recovery efforts were provided by various governmental organizations, nongovernment organizations, foreign support, and individual donations in time, money, and material. This response began before the hurricane even hit, through the opening of centers for evacuees. It continued for years after the event.

Emergency response

Response to Hurricane Katrina was immediate. The Louisiana, Mississippi, Alabama, and Florida National Guards all responded to the disaster. The Louisiana National Guard became involved before the hurricane even made landfall by delivering enough food to the Louisiana Superdome to feed 15,000 people for three days. The CDC, FEMA, Coast Guard, Air Force, Navy, and the American Red Cross were involved in the immediate disaster response. This included rescuing those stranded in floodwaters, treating injuries, and providing food and shelter to those who could not return home.

Long-term response

Hundreds of organizations worked together in the recovery of New Orleans and the Gulf Coast region. Many people donated money to help with building homes; volunteered their time; and brought food, water, supplies, and equipment to the area. Many provided shelter for families who needed a place to stay.

The U.S. government and military played a major role in both the immediate and long-term disaster response. Organizations such as FEMA and the CDC developed recovery plans, and government money was directed to all aspects of the recovery effort, including search and rescue, food and supplies, and housing. The military searched for survivors and delivered supplies. Other areas of the government, such as the Department of Education, coordinated the enrollment of displaced students in new schools throughout the United States. The Department of Labor established more than 10,000 temporary jobs for eligible displaced workers in Mississippi.

Other organizations, such as the American Red Cross, Second Harvest, the Salvation Army, and Camp Hope, volunteered time and donated money toward the effort. Some organizations provided medical care or communication through ham radios to locate survivors; others offered support through pastoral care and counselors.

Although at first the United States was reluctant to accept foreign aid, more than three dozen countries offered aid to the United States, some of which was later accepted. The European Union provided medical teams and supplies, including tents, first aid kits, and prepared meals, and Mexico sent money along with food, water, vehicles, and medical supplies. In the end, most of what was offered was not accepted by the United States, including 54 of the 77 offers from Canada, Britain, and Israel.

Private companies also played a large role in the short and long-term response. Pharmaceutical companies donated medicine and money to help rebuild hospitals and healthcare centers, whereas various transport companies donated trucks to deliver food and water. Papa John's Pizza, United Health Group, and the Coca-Cola Company all donated products to the effort. Some companies, such as amazon.com, listed links to the American Red Cross on their websites to help increase the number of incoming donations.

Although the support for Katrina victims was enormous, in fact, one of the largest in U.S. history, many people criticized how the disaster was handled. FEMA came under fire for being unorganized and unclear about who was in charge and what the recovery plan entailed. This criticism grew in some cases to be against the entire U.S. government, including against President George W. Bush. Another problem was maintaining law and order. In one case police officers killed two and injured four unarmed people trying to cross a bridge in New Orleans. Too, scams developed that funneled donations to criminals while pretending to collect for the afflicted area and victims.


Over 1,800 people died from Hurricane Katrina and the related flooding. Additionally, an estimated 1.5 million people were displaced and 275,000 homes destroyed. The most common long-term problems associated with the hurricane were the shortage of shelter for those who had no home to return to and the damaged economy along the Gulf Coast, which caused a major job shortage. Long-term effects included mental health problems, such as post-traumatic stress disorder and depression. It was found that mental health problems doubled after the hurricane. Nevertheless, although it was expected that suicide attempts would also increase, thoughts of suicide actually decreased among those with mental health problems.

As of August 2011, 90% of the New Orleans population had returned and employment was at 87% of what it was before Katrina. Unemployment in New Orleans was 8.0%, lower than the national average of 9.2% at the time. Slowly the city rebuilt and for most of the population life returned to normal.

A manmade embankment built to handle the overflow of water from a river.
Storm surge—
An abnormal rise in sea level caused by strong onshore winds.
West Nile virus—
A disease spread primarily through the bite of an infected mosquito. West Nile virus affects the central nervous systems of humans and animals bitten by infected mosquitoes. If not properly treated, West Nile virus can cause paralysis, coma, and death.


In comparison to many past natural disasters, including the Indian Ocean tsunami in 2004 and the 2010 earthquake in Haiti, the United States was relatively well prepared for the disaster, reducing the number of causalities and allowing for recovery efforts to begin immediately. Perhaps the response could have been better, and a clearer chain of command and disaster plan would have reduced the confusion that slowed recovery efforts. However, new and improved levees have been built to protect cities such as New Orleans against flooding. Hurricanes are not uncommon the in Gulf Coast region, making it important for cities and states to be prepared. The Gulf Coast was hit by another hurricane at the end of August 2012. This hurricane again caused massive flooding leading to the loss of power in over 900,000 homes, killing at least eight, and damaging over 17,000 houses.

See also Cholera ; Hurricanes ; Levee ; Posttraumatic stress disorder ; West Nile virus .



Anderson, F. Christine, et al. The New Orleans Hurricane Protection System: What Went Wrong and Why. Reston, VA: American Society of Civil Engineers, 2007.


Richardson, Harry W., et al. “Natural Disaster Analysis after Hurricane Katrina: Risk Assessment, Economic Impacts, and Social Implications.” Journal of Regional Science 50, no. 4 (2010): 895–96.


“Hurricane Katrina.” The New York Times. http://topic/subjecthurricane-katrina (accessed May 17, 2018).


American Red Cross, 2025 E St., Washington, DC, 20006, (202) 303-4498, (800) 733-2767, http://www.redcross.org .

Centers for Disease Control and Prevention, 1600 Clifton Rd., Atlanta, GA, 30333, (800) 232-4636, cdcinfor@cdc.gov, http://www.cdc.gov .

Federal Emergency Management Agency (FEMA), PO Box 10055, Hyattsville, MD, 20782, (202) 646-2500, (800) 621-3362, http://www.fema.gov .

National Hurricane Center, 11691 SW 17th St., Miami, FL, 33165, (305) 229-4404, NHC.Public.Affairs@noaa.gov, http://www.nhc.noaa.gov .

Tish Davidson, AM

  This information is not a tool for self-diagnosis or a substitute for professional care.