Hurricane Katrina Facts, Damage, and Costs

What Made Katrina so Devastating

woman with dog after Hurricane Katrina
••• Photo by Chris Graythen/Getty Images

Hurricane Katrina was a Category 5 hurricane that hit Louisiana on August 29, 2005. It was the most destructive natural disaster in U.S. history. It impacted 93,000 square miles. Its storm surge crested at 27 feet. 

Katrina was massive before it even made landfall. Its hurricane force winds reached 75 nautical miles east of the center. Its maximum winds stretched 25 to 30 nautical miles. It forced the evacuation of 75% of the 819 manned oil platforms in the Gulf of Mexico. That reduced oil production by a third. Katrina did most of its damage after the National Hurricane Center reclassified down to a Category 3 hurricane. Like most hurricanes, it slowed down when it hit land.

The Facts on Hurricane Katrina's Damage

Damage and Insurance: Hurricane Katrina cost a staggering $125 billion. Insurance covered only $80 billion of the losses, according to Swiss Re. Flooding in New Orleans caused half the damage. It destroyed or rendered uninhabitable 300,000 homes. It left in its wake 118 million cubic yards of debris. That made cleanup efforts a mind-boggling challenge.

Economic Impact: Katrina's true cost was $250 billion, according to the University of North Texas Professor Bernard Weinstein. He includes both the damage and its economic impact. Weinstein estimated uninsured losses at $215 billion and insured losses at $35 billion. The worst flooding occurred in New Orleans' 9th Ward. It was a low-income area that was mostly uninsured. These facts were discussed at the university during Katrina’s third anniversary on August 28, 2008.

The U.S. economy grew 3.6% in the third quarter, July through September. Afterward, it plummeted to 2.6% in the fourth quarter, from October to December. That's when production losses, such as gas pipe disruptions, showed up. The economy was healthy enough to shake it off. According to the National Accounts of the Bureau of Economic Analysis, it returned to a robust 5.4% growth rate in gross domestic product by the first quarter in 2006. 

Oil Costs: Katrina damaged 19% of U.S. oil production. It destroyed 113 offshore oil and gas platforms when combined with Hurricane Rita which followed soon afterward. They damaged 457 oil and gas pipelines and spilled almost as much oil as the Exxon Valdez disaster. That caused oil prices to increase by $3 a barrel. Gas prices almost reached $5 a gallon. In response, the U.S. government released oil from the Strategic Petroleum Reserves. Katrina's impact is reflected in historical oil prices.

The Toll on Humans and Pets: Of more importance was the impact on people and animals. Katrina displaced 770,000 residents. That's more than the Dust Bowl migration during the Great Depression. Seventy-five thousand returned only to find their homes destroyed.

Katrina's death toll was 1,836 people. Old age was a contributing factor. Of those who died, 71% were 60 years or older. Half of them were 75 or more. There were 68 in nursing homes, possibly abandoned by their caretakers. Two hundred bodies went unclaimed. Over 700 people were unaccounted for. The storm killed or made homeless 600,000 pets. 

What Went Wrong

Katrina was devastating because of its path. Its 28-foot storm surge exposed engineering mistakes in New Orleans' levees. It destroyed 169 miles of the 350-mile system. That flooded 80% of the city. Floodwaters did not recede for weeks. Some neighborhoods were eradicated and never recovered.

If the levees had held, flooding would have been reduced by two-thirds. The U.S. Army Corps of Engineers did not update all the levees with concrete support pilings. Some levees were not high enough. Others were built on soil that crumbled under the flooding.

Why Katrina Was So Destructive

The hurricane caused $260 million in damage to New Orleans' port, although it was open to ships a week later. The city's tourism industry generated $9.6 billion a year before Katrina. It attracted 7.1 million visitors each year. It only received 2.6 million tourists in 2006. 

Katrina struck the heart of Louisiana's sugar industry and destroyed 40% of the crop. The American Sugar Cane League estimated the annual crop valued at $500 million. This area of Louisiana had 50 chemical plants, producing 25% of the nation's chemicals. The nearby Mississippi coast was home to 12 casinos, which took in $1.3 billion each year. The storm also damaged oyster beds and the local shrimping industry. 

Despite Hurricane Katrina's overwhelming damage, there is a light on the horizon. A report from the University of New Orleans found people were flocking back to the city. In 2017, there was a record of 10 million visitors. 

How Katrina Compares to Other Hurricanes

Katrina's extensive damage was unusual. Typically, hurricanes that hit the densely populated East Coast cause the most damage.

The second most destructive hurricane cost $125 billion. Hurricane Harvey was a Category 4 storm that dropped more than 50 inches of rain. The resultant flooding covered two-thirds of Houston, Texas in August 2017.

Hurricane Maria is the third worst, creating $90 billion in damage. This Category 5 hurricane devastated Puerto Rico in 2017.

Hurricane Sandy hit New York and New Jersey in 2012. It left $70.2 billion in damage. Although it was a tropical storm, not quite a hurricane, it hit highly developed areas.

The fifth, Hurricane Irma cost $50 billion. It was a Category 5 storm when it hit Puerto Rico on September 7, 2017. It was a Category 4 when it hit Key West, Florida. It was the largest Atlantic storm ever. Its 185 mph winds lasted for 37 hours. It was fed by 86 degree water, unusually warm for the Atlantic. If Irma had hit Miami, the damage could have reached $300 billion, according to insurance firm Swiss Re. 

Global warming could create more hurricanes the size of Katrina. Warmer temperatures allow the atmosphere to hold more moisture. Rising sea levels make flooding more likely near Gulf Coast cities. Global warming also stalls weather patterns in the Gulf region. As a result, hurricanes linger longer.

Three Ways Global Warming Made Katrina Worse

Global warming contributed to Katrina's impact in three ways. First, flooding was made worse by rising sea levels. Between 1880 and 2015, the average global sea level has risen 8.9 inches. That’s much faster than in the previous 2,700 years. Unfortunately, the pace is picking up. Between 2000 and 2010, the sea level rose 1.84 inches

Second, since 1880, the earth’s average temperature has risen about 1 degree Celsius or 1.9 degrees Fahrenheit. Global warming increases the temperature of the ocean's depths. This contributes to a hurricane's ferocity. It also creates more humidity in the air and fewer winds around the storm. Warmer air holds more moisture, so it's less likely to rain. But when it does, the water descends in buckets. That makes for greater rainfall during a hurricane.    

Third, hurricanes now linger in place longer. Their pace has slowed by 10% since 1949. Climate change slows weather patterns by abating the jet stream. That’s a north-south undulating band of wind high in the atmosphere that blows at speeds up to 275 miles an hour, from west to east. It's driven by temperature contrasts between the Arctic and temperate zones. But the Arctic is warming faster than the rest of the globe. That slows down the jet stream. That allows Gustav and other storms to hover over one area and create more damage.

According to M.I.T. models, there will be more hurricanes by 2035. Category 3, 4, and 5 will be 11% of them. There will be 32 super-extreme storms with over 190-mile-per-hour winds are also being predicted to happen. These are more powerful than a Category 5. Many meteorologists are now calling for a Category 6 designation.