Wednesday, December 26, 2001
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Wednesday, December 26, 2001 |
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Peachtree City facility watching to stay ahead of floods By JOHN
MUNFORD
A combination of computer power, radar power and man power helps forecasters at the National Weather Service in Peachtree City predict potential floods for the entire Southeast United States. Meteorologists and hydrometerologists use data from computerized radar screens and information from field samples taken by volunteers to predict when a certain river or major waterway could overflow, said John Feldt, the meteorologist in charge of the local weather office. They also can predict how severe the flooding could be, he added. The more rainfall an area has received in the weeks leading up to the heavy rainstorm, the chances increase that the storm will cause flooding. "We've been so dry here that rain won't do much," Feldt said. "... But if we've had some significant rainfall amount in the past few days or month, we could be at risk for a flood." The center basically focuses on major rivers, with the nearest monitored river being the Flint River. Other major Georgia rivers they keep an eye on include the Oconee, the Chattahoochee and the Savannah. Once an area is projected to experience flooding, broadcast news agencies such as The Weather Channel and CNN are contacted to alert the public in the area, Feldt said. "We can give people time to protect their community," Feldt said. "... The two biggest threats in a flash flood are people trying to drive their cars across a flooded stream, and kids playing in and around flooded areas." Weather officials also keep emergency crews in the area up to date, giving them information that can determine whether an evacuation is necessary. Even if emergency officials call for an evacuation, it's important to tell them where not to send evacuees due to possible floods in nearby areas, Feldt said. "The real threat is inland," Feldt said, explaining that was a lesson learned during Hurricane Floyd in 1999. "We don't want to evacuate people in one area of danger to a greater area of danger." Flood forecasters have also been asked to give briefings to the vice president of the United States on occasion, Feldt noted. "We also give briefings to senators In major flood events, the weather service has a field survey team that can be sent out to provide more data to be analyzed so the flood's stages can be tracked closely, Feldt said. Several clicks of a mouse and taps on a keyboard, and Feldt calls up a color-coded map showing the rainfall an area has received over the past 30 days. The computer uses data from 22 different radars and overlays the estimated rainfall from the radar system with data from field volunteers to make sure the radar estimate is correct. Radar simply isn't as accurate as actual field samples, Feldt said. So the data from volunteers is crucial, he added. Each county in the Southeast region typically has one or two volunteer observers. Their data and the radar results are combined to give the meteorologists and hydrometeorologists ammunition to predict floods many hours in advance. Sometimes, the weather service's flood forecasting division can inform the Army Corps of Engineers a day in advance of a potential flood so dams in the area can let more water flow by before the storm event strikes, Feldt said. While the flood forecasters are particularly busy during hurricane season, they also have a number of other projects they assist with, such as the management of water reservoirs, predicting how much they will recharge over a given period of time, Feldt said. Water flow data is also shared with utilities, such as Georgia Power, that use water to generate electricity with hydrogenerators and need to withdraw water from rivers to cool the turbines of nuclear power plants. The office is also providing data in the state "water wars" so state officials can bargain over water management practices with other states. For more information, visit the flood forecasting center's Web site, www.srh.noaa.gov/serfc.
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