Florida's Hurricane Problem

Sept. 10, 2004 -- One has to go all the way back to 1964 to find a year when Florida had three major hurricanes.

Lyndon B. Johnson was in the White House. The Beatles were a novelty act. Universal Newsreels still played in movie theaters.

"They call her Dora, but she's no lady," goes the narration of one. Hurricane Dora passed over St. Augustine and Jacksonville, and then up the Georgia coast. "If you had to put it to a vote, Dora was the most unpopular girl in town."

The other hurricanes to hit Florida in 1964 were Cleo and Isbell. But somehow, in all the years since then, Florida has defied the odds.

Hurricane forecasters, asked why the state is having such a rough year, turn the question around — why is it, they say, that Florida hasn't been hit more often?

"We would have expected more strong storms to hit the U.S., especially Florida," said Chris Landsea, a hurricane researcher at the National Oceanographic and Atmospheric Administration. "I guess I'm more surprised that Florida was spared."

The Atlantic Multi-Decadal Mode

In 2001, Landsea and three colleagues published a paper in the journal Science, reporting that hurricanes come and go in cycles of several decades. Going through meteorological records, they found the number of major storms had been consistently high from the 1940s to around 1970, then had dropped significantly from 1971 to 1995, and had returned to high levels since then.

The stormy periods, Landsea said, are three times worse than the quiet ones. "The total number of storms, tropical storms and hurricanes doesn't seem to jump around too much on these long time scales, but it's the number that reach the major hurricane status," he said.

To meteorologists, "major" means a Category 3 hurricane or higher — with winds of more than 110 mph. That implies, at the least, "extensive damage to small buildings."

Why the upturn in the last 10 years? The reasons are complex and sometimes subtle. The tropical Atlantic may be warmer, though by as little as 1 degree Fahrenheit. Upper-altitude winds are also weaker, so when a hurricane forms, there's less to distort its spiral shape.