When a hurricane undergoes rapid strengthening—sometimes called bombing out—just before it makes landfall, it creates a worst-case scenario for forecasters and coastal emergency management officials. And once a hurricane begins bombing out, it can build up an unstoppable momentum.
"When a hurricane intensifies, it's like a snowball rolling down a hill, increasing in size," said meteorologist Joe Bastardi of AccuWeather, a commercial weather forecasting service. "If it gets everything going right, it can ramp up quickly."
Murderous Punch
Some of the most notorious hurricanes in U.S. history have cranked up a murderous punch just as they were about to come ashore. The last time it happened was 1992, when Hurricane Andrew climbed from a Category One to a Category Five storm in only 30 hours before making landfall south of Miami.
The rapid increase in Charley's strength was a bit of a surprise to forecasters, although they knew it would become a powerful hurricane.
"It could have become a Category Five if it had had another six hours over water to develop, but of course we'll never know for sure," Lyons said. "Rapid intensification is always somewhat of a surprise, since most typical hurricanes (increase by) about 10 or 20 miles an hour (16 or 32 kilometers an hour) per day."
Phil Klotzbach, a research meteorologist at Colorado State University, said the fact that hurricanes already are forming east of the Leeward Islands—which are located at the northeast edge of the Caribbean Sea—is an ominous sign. "When we get storms forming east of the islands in August, it tends to mean that conditions are ripe for an active season," Klotzbach said.
September 10 is considered the peak of the hurricane season, when storms are most likely to form.
Before the start of the 2004 hurricane season, renowned forecaster William Gray of Colorado State predicted three major hurricanes would form. Since July 31, four hurricanes have formed, and two of them—Alex and Charley—have become major storms.
Hurricane Forecast Unchanged: Busy Season
"The forecast that we issued a couple of weeks ago—that it would be a busy season overall—I don't see anything to change that at this point," said Chris Landsea, a meteorologist at the U.S. National Oceanic and Atmospheric Administration in Miami. "The Atlantic and the Caribbean have warmer than normal water temperatures, and there's lower wind shear. It will not be that busy every single day as it has been for the last two weeks, and I wouldn't be surprised if it calms down [briefly]."
Meteorologists think hurricane cycles wax and wane over several decades. From 1920 to 1959, 73 hurricanes—including 30 major storms—struck the United States.
The activity diminished between 1960 and 1999. During that period, 57 hurricanes struck the United States, including 21 major storms. While the hurricane cycle was down, the population dramatically increased on the Atlantic and Gulf coasts.
But meteorologists think the cycle shifted back to a period of increased activity around 1995. And unlike during the active period during the first half of the 20th century, there are millions more people living near the ocean today.
That means that if hurricanes again prowl the coastal waters in a week or two, millions of people will face a torturous decision—do they stay when a storm is near, or do they evacuate?
For the professionals, that's a no-brainer. "People must, must, must be prepared to go to a safe haven," said the Weather Channel's Lyons.
Willie Drye is the author of Storm of the Century: The Labor Day Hurricane of 1935, published by National Geographic Books. He lives in Plymouth, North Carolina.
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