Ten worst places to be in a storm

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New Orleans and Lake Okeechobee, Fla., top a list of areas experts say are most vulnerable to hurricanes

New Orleans and Lake Okeechobee, Fla., top a list of areas experts say are most vulnerable to hurricanes

A dubious distinction, they are the 10 American cities and communities most vulnerable to hurricanes — areas scientists say are very much in harm’s way. The International Hurricane Research Center released “the list that nobody wants to be on” in October, plenty early to prepare for the 2007 hurricane season.

Dr. Stephen P. Leatherman, the center’s director, says any place along the East and Gulf coasts is liable to take a hit, but some areas are much more vulnerable to hurricanes than others. The reasons these cities are on the list should raise some red flags for those who live on the coast or are considering it, he says.

For instance, Mississippi’s shoreline is ultravulnerable to surge. The land is low-lying. Mississippi Sound is shoal, which prevents high water from receding back into the Gulf. And the Chandeleur Islands to the west and Horn, Petit Bois and Dauphin islands to the east create a funnel that channels surge toward the coast, then traps it there.

“Coastal Mississippi is preordained to get storm surge,” Leatherman says of the No. 4 area on his list. “It gets the highest storm surge in the country.” Katrina flattened Waveland, Miss., with a 30-foot surge, and it could happen again … and again.

“[Yet] coastal property in Mississippi is more expensive now than it was before Katrina,” he says. “How are you going to build anything there? Anything built on that coast is subject to being wiped out again.”

Surge is a red flag, as are levees. Nos. 1 and 2 on Leatherman’s list — New Orleans and the towns around Florida’s Lake Okeechobee — are protected by levees. “Levees fail,” he says.

New Orleans’ levees failed during Hurricane Katrina, and they have failed at least 20 other times, in some fashion, since their construction in 1966, he says. The 15-foot levees were designed to withstand a Category 3 storm. Winds in New Orleans never exceeded Category 1, yet they whipped up a 12-foot surge on Lake Pontchartrain that undermined the levees. The Army Corps of Engineers has been reinforcing and rebuilding them, but Leatherman says they won’t stand up to a Category 4 or 5 storm, maybe not even a Category 3.

“Levees are going to fail,” he says. “The sooner we realize that the better, but no one wants to admit it.”

Some 2,500 people died in 1928 when a hurricane sent a powerful wave over the earthen dike around Lake Okeechobee, flooding nearby towns. The Army Corps of Engineers rebuilt the dike bigger and stronger after that hurricane, but Leatherman says the 40,000 people living today in Belle Glade, Pahokee, Clewiston and other small towns around the lake remain in jeopardy of another breach and another massive flood if a storm of Katrina’s magnitude were to rip through. The Engineers has adopted a 10-year plan to strengthen the dike, but Leatherman says low-lying land and levees are vulnerable in a catastrophic storm.

Leatherman, a student of hurricanes for three decades, and Florida International University’s Miami hurricane center used 12 criteria to evaluate an area’s vulnerability to hurricanes. Hurricane frequency, storm intensity and levee or dike failure were the most important considerations. Other physical factors included storm surge and freshwater flooding potential, as well as coastal erosion trends and island breaching history. He also used some socioeconomic indicators: populations at risk, evacuation distance and routes, what is at risk, and local-state capabilities to respond to a hurricane.

His Top 10, along with the reasons for their inclusion, are:

1. New Orleans. It’s low-lying, protected by levees, and on the flight path of late-season hurricanes that spawn in the western Caribbean and rev up in the warm waters of the Gulf of Mexico.

2. Lake Okeechobee. It’s low-lying, protected by levees, and a prime target since Florida is the country’s most active hurricane zone. (Four of the Top 10 most vulnerable cities are in Florida).

3. Florida Keys. They are low-lying, difficult to evacuate — only one highway runs the 125-mile length of the island chain — and are located in a very active hurricane zone. “It’s a nightmare to evacuate the Keys,” says Leatherman. A Category 4 or 5 hurricane could swamp the Keys and trap many of its residents.

4. Coastal Mississippi. It’s low-lying and located on a shallow sound where barrier islands funnel and trap surge. Also, it’s on a part of the coast susceptible to hurricanes spawned in the Gulf of Mexico.

5. Miami-Fort Lauderdale. They are located in South Florida — a prime target for hurricanes coming both out of the western Caribbean and the Atlantic. The population is large, evacuation routes are inadequate, and a lot of poor people who can’t evacuate or protect their homes live there. The region also has enormously valuable real estate — high-rises, condominiums, luxury waterfront homes and office buildings. “If a major hurricane, a Category 5, comes through, the loss could be $100 billion,” Leatherman says.

6. Galveston-Houston. Galveston is on a low-lying barrier island vulnerable to surge on the sound side, despite its oceanside seawall. The city lost 8,000 people in a 1900 preseawall hurricane that flooded the island, according to the National Hurricane Center. Houston has a large population, supervaluable real estate and vulnerable high-rises. And it’s low-lying, set among bayous that flood and in the path of hurricanes coming out of the Gulf. “A lot of big ones come up that way,” Leatherman says.

7. Cape Hatteras, N.C. The Outer Banks are low-lying barrier islands — narrow, exposed, subject to massive storm erosion that cuts channels across the islands. They have just one evacuation route, attract large numbers of visitors in summer, and boast a lot of valuable real estate. The Outer Banks are a prime target for hurricanes that cross the Atlantic from the Azores and turn north before Florida. Leatherman says the islands are second only to Florida in numbers of hurricanes hitting or brushing them.

8. Eastern Long Island, N.Y. “It’s been a long time since they’ve seen a big hurricane,” says Leatherman. The last big one was Gloria, a Category 3 that hit in 1985. The east end is low-lying. Gloria’s 15-foot storm surge flooded Southampton, cut off Montauk, and “pancaked” a lot of waterfront development. He says real estate in the Hamptons is among the nation’s priciest.

9. Wilmington, N.C. Wilmington and the resort communities around it — Wrightsville Beach, Topsail Island, Oak Island — have been hit a lot in recent years. Wilmington’s downtown on the Cape Fear River is low-lying, as are the barrier islands, and Mason’s Inlet is migrating — it is very prone to erosion.

10. Tampa-St. Petersburg, Fla. The west-coast Florida shoreline is low-lying and prone to flooding, its population is huge, and Tampa Bay is shoal. A 15- to 20-foot storm surge is par for the bay if a big hurricane hits. Evacuation routes are inadequate, and at least a half-million area residents live in trailer parks. “It has not been hit directly since 1921,” Leatherman says. “It’s had some good luck, but also it’s not on a major route for hurricanes.” Yet if a Category 4 or 5 hit, the destruction and loss of life could be enormous.

Leatherman says he’ll be updating his Top 10 list annually, refining his analysis and looking at new data. He hopes the information will heighten awareness of hurricanes, especially in coastal areas.

“A lot of people just don’t think it’s going to happen to them,” he says.