Those day-long soakers are getting more frequent, and a coalition of environmental groups says it's because of global warming. A warmer atmosphere holds more energy and absorbs more water, both of which are unleashed during storms.
The frequency of extreme rainfall, as defined by Environment America, has increased 24% between 1948 and 2006. Extreme rainfall for any one of the 3,000 location analyzed is defined as a day of rain that meets or exceeds a one-day record for an individual year. Put another way, the so-called "Storm of the Year" is coming more frequently than just once a year.
The group worked with federal and state researchers that had done similar studies of individual locations. The research will not be published in a peer-reviewed scientific journal.
A separate analysis publicized Tuesday predicts that strong storms like thunderstorms and tornadoes will also become more common, as global warming creates weather patterns that support the formation of stronger storms.
The Environment America report asserts that global warming is already having an effect. New England and the Mid-Atlantic showed the largest increase in storm frequency. Extreme rain has real consequences, including flooded roads, airports and subways that can interrupt commerce; damage to homes and property; sewage overflows and erosion.
"At rate we're going, what was once the storm of the decade will soon seem like just another downpour," said Environment Americas Washington DC Director Anna Aurilio.
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