'Lucky break' behind 9-year hurricane drought in U.S.

Tuesday, May 5, 2015, 8:09 AM - No major hurricanes measuring Category 3 or greater have made landfall in the U.S. for the past nine years. Researchers say this type of 'hurricane drought' hasn't been seen since record-keeping began in 1851.

The current streak beats the previous record of eight years, set between 1861 and 1868.

While the drought is unusual, the factors causing it couldn't be more ordinary. A team of researchers have looked into the streak and have concluded it can be chalked up to nothing more than dumb luck.

“There’s been a lot of talk about how unusual the string is, and we want to quantify it,” hurricane researcher Timothy Hall of the NASA Goddard Institute and lead author of the study says in a statement.

“When we looked qualitatively at the nine-year drought, they aren't inactive seasons."

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In other words, there hasn't been a substantial change in the number of tropical cyclones over the years and the amount of energy driving them hasn't dwindled.

“I don’t believe there is a major regime shift that’s protecting the U.S,” Hall says.

Hall's team used a computer model to account for the common elements known to impact hurricanes, like high sea surface temperatures. Researchers then simulated the years 1950 to 2012 a thousand times to gain a better understanding of how many times computer-simulated hurricanes were able to make landfall from Texas to Maine.

That provided researchers with enough data to predict the odds of a major hurricane making landfall in the U.S.

Based on that information, Hall and his colleague Kelly Hereid concluded there isn't anything unusual contributing to the hurricane drought.

The drought could extend into this year, with forecasters predicting a quiet tropical storm season due to a moderate El Niño event and relatively cool conditions in the tropical Atlantic.

No Category 3 storms have made landfall in the past nine years, but hurricanes of lesser strength have.

Hurricane Ike, for example, was only a Category 2 when it came ashore in the U.S.

Hall's complete study has been published in Geophysical Letters.

Source: AGU Blogosphere | Geophysical Letters