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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