for National Geographic News
Violent winds, killer waves, torrential rains, and flash flooding are the calling cards of a hurricane.
And if scientists are correct,the North Atlantic, Caribbean, and Gulf of Mexico regions can expect increased hurricane activity in the next 10 to 40 years.
The number of major hurricanes has more than doubled in the last six years. The increase is part of a long-term climate shift that is likely to persist for several decades, said Chris Landsea, a meteorological researcher with the U.S. National Atmospheric and Oceanic Administration (NOAA) Hurricane Research Division and co-author of a study on the findings in the July 20 issue of the journal Science.
"We've seen a big increase in the number of hurricanes since 1995, and in the next 30 years we're going to see a lot more," he said. "It's part of a natural cycle, and it's going to be a real eye-opening for the people living on the coasts who have never seen a hurricane before."
The findings may be a cause for concern, the researchers warn, saying those responsible for emergency preparedness and civilian safety should reevaluate current response strategies to insure they are adequate.
Until now, the conditions responsible for the formation of tropical storms have been poorly understood.
A lack of sufficient data and the complex interactions between wind, water, temperature, and other factors that contribute to the development of a storm have made storm prediction a risky endeavor.
By using a combination of satellite imagery, computer modeling, and high-tech monitoring of numerous factorsfrom sea-surface temperatures to atmospheric conditionsthe team of scientists has identified a multi-decade pattern of likely hurricane activity. These long-term patterns can be classified as quiet, near normal, or active.
During the 20th century, a period of high hurricane activity occurred from the 1920s through the 1960s, followed by reduced activity from 1971 to 1994.
The researchers predict that we are now on the cusp of a 10- to 40-year shift toward increased frequency of hurricanes.
"During any of these periods, the actual number of storms can jump around a lot from year to year," said Landsea. "1997 is a good example. Strong El Niño effects suppressed hurricane activity for that year even though we were in the middle of an 'active' period."
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