ATLANTA — Air traffic delays are more than just annoying: On average, they probably cost the U.S. economy more than hurricanes do.

Most media reports focus on extended delays that leave passengers stranded in airports for days or trapped on the tarmac for hours, said Bob Maxson, director of the National Oceanic and Atmospheric Administration’s Aviation Weather Center in Kansas City, Mo. But the vast majority of delays are relatively minor and stem from localized weather events such as heavy rain, limited visibility or strong crosswinds, he reported January 19 at the annual meeting of the American Meteorological Society. These small delays nevertheless add up to big costs, he notes.

From January 2004 through December 2008, about 78 percent of all airline flights in the United States were on time, Maxson said. Greg Forbes, a meteorologist at The Weather Channel in Atlanta, reported at the same meeting that more than 5 million flights took to the air in the United States in 2009, but only 0.08 percent of them experienced delays of more than two hours.

Episodes of bad weather, particularly thunderstorms, are the most common cause of air traffic delays, Maxson said. And all airspace is not created equal, he notes: Large swaths of the Midwest can be covered with fierce thunderstorms that have little effect on air traffic, but one small cluster of storms in just the wrong place — the approach path for flights into high-traffic airports in Newark, N.J., or New York City, for example — can trigger delays affecting an immense number of passengers. In an air traffic system that operates near capacity, any delays in one region tend to spread like ripples and trigger delays elsewhere.

Forbes agreed: “It doesn’t take severe weather to disrupt air traffic.”

A 2008 analysis by the Joint Economic Committee of the U.S. Congress suggested that domestic air traffic delays in 2007 alone cost the economy as much as $41 billion, including $19 billion in increased operational costs for the airlines and $12 billion worth of lost time for passengers.

Those figures are likely to be overestimates, Maxson said. But even if the economic costs of air traffic delays are only $15 billion per year, for the years 2000 through 2008 those costs still would have added up to more economic damage than the hurricanes that struck the United States during that same interval, Maxson said. While storm damage was about $131 billion during that nine-year period — including damages exceeding $90 billion in 2005, the year of Katrina and Rita, and the nearly $20 billion burden caused by the four hurricanes that raked across Florida the previous year — air traffic delays would have cost the economy about $135 billion, Maxson estimates.

Image: Simulated 2006 air traffic over the United States at 10:41 a.m. PST./NASA

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