• The 2005 season set a new record on the net tropical cyclone (NTC) scale. NTC is a measure that takes into account the number of storms that form in a season, the intensity of the storms, and how long they last. 2005's NTC index is 249, which easily surpasses the previous record of 230 set in 1950.
Stormy Season Ends
On the storm-battered U.S. Gulf Coast, which was raked by four intense hurricanes, jittery residents are relieved that the long, stormy summer has ended.
"We're certainly happy the season is over," said A.J. Holloway, mayor of Biloxi, Mississippi, which was devastated by Hurricane Katrina on August 29. "I hope we never see anything like this again."
The violent summer of 2005 also brought the debate about global warning's possible effects on hurricanes to public attention.
Some meteorologists say there is a direct link between the increased hurricane activity and the presence of so-called greenhouse gasses in the atmosphere, which is causing hotter summers and warmer winters.
Others, however, say the stormier summers are caused by a natural cycle of ocean currents that affects the salinity of the water. When the salt content is slightly higher—as it is now in the Atlantic—the water is warmer, and more hurricanes form.
The cycles are thought to last from 25 to 40 years.
"I believe global warming may be having some effect on hurricanes, but it's very small," said Blackwell, the Mobile, Alabama, meteorologist. "It's not responsible for the [increased] activity. This year would have happened anyway."
There have been earlier periods of active hurricane seasons that alternated with less-active ones. During the early 20th century, hurricane seasons were less active. But an active cycle began in the late 1920s and lasted until about 1969.
Another less active cycle lasted from 1970 to 1994. But the summer of 1995 saw a dramatic increase in the number of storms. That active cycle is still continuing and is expected to last at least another ten years, perhaps longer.
Although the hurricane season runs from June 1 to November 30, hurricanes sometimes form out of season.
"In the last few years, we've had a few December storms," Blackwell said. "It's not out of the question this year either."
On December 6, Klotzbach and other researchers at Colorado State will release their first prediction for the 2006 hurricane season.
"I would be surprised if 2006 is a very inactive season," Klotzbach said.
Willie Drye is the author of Storm of the Century: The Labor Day hurricane of 1935, published by National Geographic Books.
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