Earth & Sky

More rain from tropical storms than hurricanes

Scientists have found that tropical storms can do more to relieve drought than hurricanes.

This result is a step on the way to understanding how rainfall is related to climate change. Marshall Shepherd is a meteorologist at the University of Georgia.

Marshall Shepherd: In the last several years, there’s been a debate about whether global warming is leading to more hurricanes, or more frequent, intense hurricanes. We became interested in whether we could see if there’s an increase in hurricane-related rainfall as a possible signature of climate change, or global warming.

Shepherd used satellite data to determine how much rainfall was contributed by tropical storms and hurricanes in the southeastern United States.

He found that the weaker storms – the tropical depressions – contribute more rain overall than hurricanes, even during hurricane season. He said this has important implications for the southeastern U.S., which is suffering from drought.

Marshall Shepherd: In terms of rainfall and drought, really, it doesn’t take a massive category 3,4, or 5 storm. Those are the storms that get the most attention during the hurricane season. But in terms of soaking, sustained rainfall, when we hear a tropical depression or storm is on the horizon, that’s good news for water resource managers, for refilling lake reservoirs, and possibly putting a dent in the large drought.

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