A gentle storm season gives U.S. a break

But experts say hurricane activity will remain heightened long term

November 27, 2006|By McClatchy-Tribune

MIAMI -- Congratulations. The hurricane season -- a surprisingly gentle one -- is effectively over. Now, experts say, use the breather wisely and don't take too much for granted.

After two brutal seasons, the law of averages kicked in this year, and the gods of wind and rain treated us kindly. But scientists say the long-term outlook remains stormy.

We are still locked in a decades-long period of heightened activity, they say, and should not be misled by the relatively benign 2006 hurricane season, which officially ends Thursday.

"I am so thankful that someone decided to give us a break," said Stanley Goldenberg, a researcher at the National Oceanic and Atmospheric Administration's Hurricane Research Division on Virginia Key.

"But people need to realize that we are still in the active era. Within a year or two, we can expect things to bounce back up."

"The break": We had a slightly below-average season, thanks to some unexpected shifts in global weather patterns. Nine named storms formed this year, five of them grew into hurricanes, and no hurricanes struck the United States.

The potential "bounce back": a return to the above-average activity in 2004 when 15 named storms developed into nine hurricanes, four of which slammed Florida.

Or, even worse, a repeat of the hyperactivity of the record-smashing 2005 season, when 27 named storms became 15 hurricanes, four of them also hitting Florida.

"People should use this break to examine their preparedness and harden their defenses," Goldenberg said. "They should not be thinking, `Oh good, we're done with this.'"

Goldenberg is more than just a hurricane scientist.

He and his family nearly died when Hurricane Andrew leveled much of south Miami-Dade County in 1992, so he has firsthand knowledge of the terror and destruction that a hurricane can deliver.

More to the point, Goldenberg and colleague Chris Landsea led a team that published a seminal study in 2001 documenting the start of a two- to three-decade period of heightened hurricane activity.

That period began in 1995, Goldenberg said. One relatively harmless season likely represents nothing more than normal year-to-year variation within the larger trend, he and others said.

"It's not going to last," Max Mayfield, director of the National Hurricane Center, said of the dip in hurricane activity.

A brief, potentially misleading reprieve has happened before.

A mild season in 1997 -- seven named storms that became three hurricanes -- was sandwiched between two much more active years. Thirteen named storms and nine hurricanes developed in 1996; 14 named storms and 10 hurricanes materialized in 1998.

Still, before this six-month season began, virtually every expert predicted another above-average hurricane season, and all of them were wrong.

As the season progressed and the tropics repeatedly refused to cooperate with the predictions, federal meteorologists and private forecasters repeatedly lowered their forecasts -- and they still couldn't get it right.

The reasons? A late-developing El Nino and surprisingly dry atmospheric conditions over the Atlantic basin, which includes the Caribbean Sea and the Gulf of Mexico.

El Ninos occur when water in the eastern Pacific Ocean becomes unusually warm. They produce winds that can reach the Atlantic basin and suppress the development and strength of tropical systems.

Alas, El Nino is expected to fade by the June 1 beginning of the next hurricane season.

In addition, most of the storms that did form this year were pushed away from the United States and Caribbean islands by friendly atmospheric conditions.

But, again, don't take too much for granted.

"The ... signals are still there," Goldenberg said. "You just had some stuff this year that depressed it."

For one thing, the usual number of tropical waves -- the seeds of tropical storms and hurricanes -- rolled off Africa into the Atlantic this year, about 60 of them. For another, ocean temperatures were extremely warm, and warm water usually fuels tropical systems.

During August, September and October -- the peak of the hurricane season known as the "ASO" to scientists -- Atlantic water temperatures were 1.1 degree Fahrenheit higher than normal -- a significant elevation.

"It was the second-warmest ASO on record," Goldenberg said, calling it further evidence that global warming is just one of many factors involved in climate change.

William Gray and Phil Klotzbach, the scientists at Colorado State University who issue widely reported seasonal forecasts, tend to agree.

"A variety of factors interact with each other to cause year-to-year and month-to-month hurricane variability," Klotzbach said in a statement intended to explain why this year's seasonal forecasts were so off the mark.

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