NEW ELLENTON - Emergency decision-makers dealing with the Graniteville train disaster relied on the sophisticated forecasting expertise of meteorologists based at the Savannah River National Laboratory.
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A screen at the Atmospheric Technologies Group shows an example of the model created the morning of the train wreck showing how a chlorine cloud could possibly travel. The bluish area shows the path of the chlorine that escaped in the wreck. The yellow area shows where the chlorine is most dense.
Ron Cockerille/Staff
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Within hours of the early morning Jan. 6 wreck of Norfolk Southern Train 192, forecasters with the lab's Atmospheric Technologies Group created automatic updates on wind conditions and computer models of the potential path of the deadly chlorine spilling from a ruptured rail tanker.
Such timely and detailed information played a critical role in the decision to evacuate an estimated 5,400 residents the afternoon of the wreck.
It also gave Aiken County Sheriff Mike Hunt and other officials a graphic picture of the lethal path a secondary release could have taken had the dangerous process of transferring 220 tons of chlorine from damaged tank cars gone awry.
"It was very crucial to give us up-to-date wind conditions and plume models," Sheriff Hunt said. "It was not the only trigger, but it was one of the ingredients that led to that evacuation."
From a monitor-rimmed control desk in the heart of the lab, manager Robert Addis, 12 meteorologists and computer-modeling experts tracked wind conditions from eight automated monitoring stations.
The monitors are scattered around the 300-square-mile Savannah River Site and six stations in Richmond County, including Augusta Regional Airport and Daniel Field and the belt of industrial plants that rim south Augusta.
"What was most important was the forecast - what happens if the wind shifts and whether you'll have stable conditions at night," Mr. Addis said.
The lab's computers were used to model the potential path of chlorine that continued to plume from the leaking tank car for more than three days after the 2:40 a.m. wreck.
At 8 a.m., the group cranked out its first plume model, said senior meteorologist Chuck Hunter. With winds that blew steadily from the south and southwest at about 5 mph, chlorine leaking from the tanker was rapidly dispersed - a contrast to the minutes just after the wreck when a far heavier volume of toxic chlorine rose in clouds from the ruptured tanker and killed nine people.
As nightfall approached, the forecast called for cool, relatively windless conditions that would cause chlorine, with a density heavier than air, to settle back to the ground, Mr. Hunter said.
Armed with that information - and concern about the potential of a second massive release - Sheriff Hunt ordered a mandatory evacuation in a one-mile radius around the accident site.
Mr. Addis' group was originally formed to provide weather forecasts for SRS operations. But in 1996, a mutual aid pact was signed with counties that border SRS, including Richmond, Aiken and Columbia.
As part of that pact, firefighters and emergency managers have been invited to observe and train with SRS emergency and security personnel, including an exercise three months ago based on a train wreck and chemical release scenario.
All of this had a real-time payoff in Graniteville.
"A lot of what we did was part of the plan," Sheriff Hunt said. "It all worked, and it was very crucial."
Reach Jim Nesbitt at (706) 828-3904 or jim.nesbitt@augustachronicle.com.
Special Section: Graniteville Train Wreck
On January 6, 2005, a Norfolk Southern Corp. freight train carrying chemicals hit a parked train near an Avondale Mills plant in Graniteville, South Carolina. The impact caused poisonous chlorine gas to leak from three of the moving train's cars. Nine people were killed and more than 5,000 people were evacuated from the site.
For complete coverage of the Graniteville train wreck, visit our special section.
Who they are:
The Atmospheric Technologies Group at the Savannah River National Laboratory develops sophisticated forecasting models and provides emergency weather information for five counties near Savannah River Site: Columbia, Richmond, Aiken, Allendale and Barnwell.
