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The 'perfect storm' for New Orleans

Bill Proenza, the director of the National Weather Service’s southern region, and other scientists point to a series of unrelated conditions — at sea, in the atmosphere, and on the ground— that together put New Orleans under water.
/ Source: Dateline NBC

Even before it hit, it was already clear that Katrina, pin-wheeling toward the Gulf Coast, was on a collision course with a city that wasn’t — couldn’t be — ready.

Bill Proenza, the director of the National Weather Service’s southern region, and other scientists point to a series of unrelated conditions — at sea, in the atmosphere, and on the ground— that together put New Orleans under water.

Here’s what happened: The warmer than usual waters of the Gulf of Mexico gave Katrina fuel and accelerated the storm from a Category One hurricane to a Category Four in just 72 hours. Katrina moved slowly, allowing her to gain strength as she closed in on the coast.

“Warm waters of the Gulf of Mexico fed the convection. In addition to that, above the storm, we had circulation flow that allowed the storm to deepen and get stronger,” says Proenza.

And with Katrina’s high winds moving counterclockwise, Louisiana’s geography worked against it. The storm pushed the water in Lake Ponchartrain over the levees that protect the city, and a disaster was born— one that to many, came as no surprise.

“It was forseen. A lot of people talked about the worst natural disaster in this country being a direct hit on New Orleans,” says Kathleen Tierney, director of the natural disaster center at the University of Colorado.

But just as events came together at sea to create a bigger stronger Katrina, a series of unrelated conditions on shore made coastline cities less able to withstand the storm— old pumping systems that were already pushed to their limits, old levees that were built to withstand only a Category Three hurricane, old buildings that are charming to look at but that wouldn’t stand up to today’s building codes, and one valuable line of protection started disappearing years ago— coastal marshes— that have been sacrificed in the name of development.

“Wetlands provide a buffer against winds and rain,” says Tierny. “Think of wetlands as the lungs of a city or river. They are able to take up excess water and also take some off the force of the hurricane themselves.”

But when Katrina hit, much of the wetland area was already gone— developed for new roads, for shipping channels, for the petrochemical industry, and for the thousands of people who have headed for the sun belt over the last 25 years.

“There has been such intense development in some of these coastal areas that that these coastal areas have been completely transformed. During the time when much of this development took place, we happened to be in a historical period when there weren’t very many hurricanes making landfall,” Tierny adds.

But that’s already changing: 2005 is a very active hurricane season, and with more than two months to go, there may well be more storms coming.

“For this area, the worst may not be over,” says Proenza.