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Hurricane Gustav's Angle Hints at Widespread Damage

Willie Drye
for National Geographic News
August 31, 2008
 
Hurricane Gustav is expected to make a Labor Day landfall near New Orleans on Monday morning with winds that could exceed 130 miles (209 kilometers) an hour.

The storm's expected angle of approach—moving northwest or west-northwest, hugging the Louisiana coastline—could mean that an unusually long stretch could feel the full force of Gustav before it moves inland, where lack of contact with open water will weaken it.

As of 2 p.m. ET Sunday, forecasters think Gustav's eye—which will contain the storm's strongest winds—may be just offshore of Plaquemines Parish, just southeast of New Orleans, by 8 a.m. Monday.

Two other parishes—the Louisiana equivalent of counties—Lafourche and Terrebonne, just to the west of Plaquemines, are also potential landfall sites.

If Gustav follows the projected path, downtown New Orleans will probably get sustained winds of 60 to 70 miles (97 to 113 kilometers) an hour and gusts of 80 to 85 miles (129 to 137 kilometers) an hour, said Keith Blackwell, a meteorologist at the University of South Alabama's Coastal Weather Research Center in Mobile.

Still, Gustav's storm surge could push more than 12 feet (3.7 meters) of water up the Mississippi River Gulf Outlet shipping canal, which links downtown New Orleans with the Gulf of Mexico. If that happens, the narrowness of the waterway could make the surge even higher as it comes into New Orleans, and officials are worried that the surge will be higher than the levees.

(Special report: National Geographic magazine on New Orleans' hurricane vulnerabilities—full article, interactive map, videos, and more.)

Wide Path of Destruction?

Gustav's strongest winds aren't likely to extend more than about 10 miles (16 kilometers) from its eye, Blackwell said.

But because the hurricane's eye is expected to be moving in a west-northwest or northwest direction as it approaches shore, its strongest winds could rake as many as five or six Louisiana parishes as Gustav moves inland from the Gulf of Mexico.

"The area around Grand Isle [about 60 miles south of New Orleans] over toward Port Fourchon likely will receive the worst conditions if the storm moves along this projected path," Blackwell said.

Meteorologists caution, however, that landfall projections 24 hours ahead of time can be off by as much as 100 miles (160 kilometers).

Storm Surge

As of 1 p.m. ET Sunday, the National Hurricane Center in Miami had issued a hurricane warning along the Gulf Coast from Cameron, Louisiana, near the Texas border east to the Alabama-Florida border (Gulf Coast map). The warning means that, within the next 24 hours, this area probably will experience winds of at least 74 miles (119 kilometers) an hour.

Chris Sisko, a meteorologist at the hurricane center, said Gustav's eye is expected to bring a storm surge of 12 to 16 feet (3.6 to 4.8 meters) wherever the hurricane makes landfall.

The storm surge threat and the high winds have raised concerns among New Orleans and state officials about possible severe flooding in the city. New Orleans Mayor Ray Nagin has issued a mandatory evacuation order, reportedly prompting at least a million residents to flee the city.

Flooding concerns are exacerbated by memories of Hurricane Katrina, which struck New Orleans on August 29, 2005. Katrina's winds and storm surge caused breaks in New Orleans levees that resulted in catastrophic flooding in the city.

The U.S. Army Corps of Engineers has been working since Katrina to repair and reinforce the system of levees that protect the below-sea-level city from Lake Pontchartrain and the Mississippi River. But on Sunday the New Orleans Times-Picayune reported that local officials are still worried about several weak spots in the system.

The newspaper also reported that the system has had "an unprecedented amount of … improvements" since August 2005.

Looking Back, Looking Ahead

Gustav has already killed about 70 people during a trek across the Caribbean, which began August 25. The hurricane came ashore in western Cuba yesterday with winds of at least 150 miles (241 kilometers) an hour. The storm's passage across Cuba's mountains weakened Gustav considerably by the time it emerged into the Gulf of Mexico this morning.

But Gustav is expected to regain much of that strength as it moves across the very warm waters of the Gulf of Mexico—particularly the storm-fueling Loop Current—during the hurricane's run to the Louisiana coast.

Meanwhile, forecasters think the southern U.S. East Coast could be dealing with tropical storm Hanna later this week.

Gustav has impeded Hanna's development, but Hanna could begin to strengthen and move north toward the Carolinas as Gustav moves out of the picture, Blackwell said.

Willie Drye is author of Storm of the Century: the Labor Day hurricane of 1935, published by National Geographic Books.

HURRICANE BASICS




Hurricane Facts
Hurricane Safety Tips
Hurricane Photos
New Orleans' Faulty Levees (National Geographic Magazine)
Forecasting Killer Hurricanes (National Geographic Magazine)
 

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