Katrina-size hurricane would devastate South Florida, scientists say

Katrina-size hurricane would devastate South Florida, scientists say

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By Martin Merzer

Knight Ridder Newspapers

(KRT)

MIAMI Seven feet of sea water swamps 45 miles of coastline from Miami Beach through Fort Lauderdale to Deerfield Beach. Salt water surges through countless houses near the coast. Waist-deep fresh water blankets vast regions of suburbia.

Ferocious winds crush tens of thousands of roofs and gut numerous office buildings. Residents who defy orders to evacuate skyscrapers along the coast and in downtown Miami could be blown out of their apartments. Power outages persist for months.

According to simulations conducted for The Miami Herald by scientists at the National Hurricane Center and to interviews with a wide range of experts, those are realistic sketches of what could occur when South Florida is blasted by a hurricane as strong as last year’s Katrina was when it devastated the Gulf Coast and New Orleans, or Wilma when it wrecked portions of Mexico’s Yucatan Peninsula.

“It is not inconceivable that hundreds or even thousands of Floridians who fail to take action, and who fail to evacuate if they are in evacuation zones, can lose their lives,” said Craig Fugate, Florida’s director of emergency management.

The six-month North Atlantic hurricane season begins June 1, but the odds are low that a storm of such intensity and breadth will strike in any given year. Someday, however maybe this year, maybe next year, maybe during the next decade, but without question someday such a storm will ravage South Florida.

“We know that it happened in southeast Florida before and there’s no doubt in my mind that it will happen again,” said Max Mayfield, the hurricane center’s director. “I can’t tell people when, but I can guarantee that it will happen.”

The sketches produced by the experts and simulations offer a glimpse of a historic event that could transform the Miami-Fort Lauderdale area much as Katrina transformed New Orleans.

This article and the graphics and other material that accompany it in print and online aren’t intended to frighten readers. They’re intended to provide a clear-eyed assessment of how the heightened hurricane activity that’s expected in coming decades could affect a densely developed area that’s a magnet for people from northern states and South America and for vacationers all over the world.

The scenarios developed for The Miami Herald reflect the likely consequences if South Florida’s Atlantic coast were hit head-on by the Category 3 version of Katrina, which slammed New Orleans, or by the slow-moving Category 4 version of Wilma, which ravaged Cancun and other parts of Mexico’s Yucatan peninsula.

Each storm would produce extensive damage to what engineers call the “exterior curtain wall” of high-rises, which includes windows and their frames, and to tens of thousands of private homes, particularly their roofs.

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In the Katrina scenario, “I don’t mean just the tiles coming off,” said Herbert Saffir, a structural engineer and the co-developer of the Saffir-Simpson hurricane scale, which ranks storms in categories 1 to 5. “I mean the entire roof coming off.”

That, along with wind-blown rain penetrating around windows and sliding-glass doors and through other means, would allow substantial amounts of water to enter the buildings, compounding the damage.

“But what we really have to be worried about is the Category 4 or 5 storm that exceeds Katrina,” Saffir said.

Which brings us to another Wilma, even more powerful than Katrina. What would residents see after such a storm?

“Block after block after block of stripped buildings,” Saffir said. “There would be utter devastation.”

“You’re looking at major, major, major destruction,” said Charles Danger, the director of Miami-Dade County’s building department. ” . . . You will lose infrastructure and the place where people need to go to do their jobs and work in this economy. You are paralyzing a complete city.”

The weaker Wilma that struck South Florida on Oct. 24 severed power to 98 percent of Miami-Dade County and Broward County, which includes Fort Lauderdale. Electricity to some customers wasn’t restored for nearly three weeks.

It can’t get much worse than that, right?

Wrong.

“You can get a whole lot worse that that,” said Jay Apt, the executive director of the Carnegie Mellon Electricity Industry Center, a power-industry research group based at the university of the same name in Pittsburgh. “Ninety-eight percent recovered in three weeks beats 98 percent recovered in that many months. That’s what you could be looking at months without electricity.”

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Experts also worry about the likelihood of widespread flooding in suburban and some urban areas, especially in the Wilma scenario.

“This is probably not a situation with people on their roofs needing to be rescued,” Fugate said, “but they will be up to their waists in water in a lot of neighborhoods that don’t expect to be.”

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A particularly macabre fate could await anyone foolish enough to defy orders to evacuate the new residential towers that line many South Florida beaches and downtown streets.

Some are more than 800 feet tall. Hurricane forecaster James Franklin, an expert in calculating hurricane winds, said anyone living above the 30th floor of a building or about 300 feet from the ground could endure wind at least 20 mph or more stronger than the wind at the surface.

If the windows in those buildings broke, and many would, people who stayed behind could be picked up by the wind and blown away.

“They will be blown out and you will never find them,” Danger said.

To view online simulations of the devastation, go to www.krwashington.com.

(c) 2006, Knight Ridder/Tribune Information Services.

PHOTOS (from KRT Photo Service, 202-383-6099): HURRICANE-DAMAGE