"The big lesson I learned from Hurricane Katrina is that we have to be thinking about the unthinkable because sometimes the unthinkable happens." - Mike Leavitt

Hurricanes have been devastating communities for thousands of years, bringing about various combinations of rain and wind that can do everything from taking down some dead limbs to wiping out houses. They are also common enough that people who live for any length of time in a region prone to having hurricanes are inclined to accept them as something of a periodic nuisance rather than a serious danger. Modern construction styles allow houses to withstand winds in excess of 100 miles an hour, and early warning systems allow people to evacuate. Thus, most hurricanes of the 21st century take fewer lives than a serious highway accident.

As a result, the world watched in horror as Hurricane Katrina decimated New Orleans in August 2005, and the calamity seemed all the worse because many felt that technology had advanced far enough to prevent such tragedies, whether through advanced warning or engineering. Spawning off the Bahamian coast that month, Katrina quickly grew to be one of the deadliest natural disasters in American history, killing more than 1,800 people and flooding a heavy majority of one of America's most famous cities. At first, the storm seemed to be harmless, scooting across the Floridian coast as a barely noticeable Category 1 storm, but when Katrina reached the warm waters of the Gulf of Mexico, its winds grew exponentially before slamming into the southern Louisiana coast as a massive Category 5 hurricane.