Why Did Katrina Hit the Gulf Coast Hardest?

Most hurricanes develop over warm waters in the Atlantic Ocean. Hurricanes rely on the heat in ocean waters to maintain their energy. When they reach land, they begin to lose their strength. This happened when Katrina first swept across Florida as a Category 1 hurricane, or one with about 85 mile-per-hour winds.

Once Katrina moved into the Gulf of Mexico, however, the storm found a new supply of energy. At that time, waters in the Gulf were even warmer than the Atlantic Ocean. Because of this, Katrina quickly strengthened. Over the next two days, Katrina became a Category 5 hurricane, or one with winds over 156 miles-per-hour. The path of the storm posed a severe threat to regions along the Gulf Coast of the United States.

Click here to view this graphic at a larger size

Five states have coastal areas along the Gulf of Mexico: Texas, Louisiana, Mississippi, Alabama, and Florida. Hurricane warnings alerted residents there to prepare for heavy rains, high winds, and flooding. Some areas along the Gulf Coast lie at or below sea level, or the normal height of the Gulf's waters. These places were at great risk from flooding due to the storm.

People in the city of New Orleans in Louisiana have feared a storm like Katrina for many years. New Orleans is located between two bodies of water, and many parts of the city are below sea level. Lake Pontchartrain borders the city to the north. The Mississippi River flows right through the city to the Gulf of Mexico, making New Orleans a busy port for ships. The entire city was built on the Mississippi floodplain, which is the area on either side of the river that would normally flood whenever the waters rises.

What Were the Effects of Katrina on the Gulf Coast?

Engineers had built systems of levees, pumps, and spillways to help keep this water out of New Orleans. Levees act like long dams to prevent flooding. Spillways help to channel water away from places where people live. This system had prevented major floods from happening in New Orleans since 1927. Even so, the levees and spillways required constant strengthening and repairs.

Katrina was strong enough to lift water up 29 feet at some points along the Gulf Coast. On top of that, heavy rainfall caused Lake Pontchartrain and the Mississippi River to rise higher than ever before. The force of all that water weakened and broke down some of the levees along canals in the city. Within a few hours after these levees gave way, most of New Orleans was flooded.

Click here to view this graphic at a larger size

Other cities along the Gulf Coast also flooded when Katrina pushed ashore. In the state of Mississippi, Gulfport and Biloxi were both severely damaged. High winds and waters destroyed some of the bridges and highways linking these and other Gulf Coast cities. Many people living on barrier islands in the Gulf of Mexico had no way to reach the mainland. The barrier island of Grand Isle, Louisiana, was the first place hit by Katrina when the hurricane moved out of the Gulf.

Hurricane Katrina destroyed the houses and workplaces of millions of people. The Gulf Coast, once a busy area for shipping, tourism, oil refineries, and the chemical industry, will now devote most of its time to reconstruction. In time, these cities may once again become the important ports that keep our country's economy active. People from all 50 states and from around the globe are already doing what they can to help make that happen.

MAP ACTIVITY: Using your textbook, the library, and other resources such as the Internet, find as many maps as you can showing the Gulf Coast and how it was affected by Hurricane Katrina. Use these maps to show the time line of the storm and to demonstrate the various causes and effects that made it one of the largest natural disasters of our time. Suggest ways in which two or more maps might be combined to further illustrate your ideas.