Computer program helps track deadly plume

Published Oct. 14, 2001

Mary Hopkin
Herald Oregon bureau

HEPPNER - Just a few quick strokes on the keyboard and Martha Doherty finds out what direction the wind would carry the poisonous cloud if an accident ever occurred at the Umatilla Chemical Depot.

A few more keystrokes and Doherty, the data analyst for Morrow County Emergency Management, can predict where the cloud would travel during the next 24 hours.

The computer program that helps Doherty tell the future is known as D2Puf.

The software was installed in the emergency operations centers at the depot and Umatilla and Morrow counties this summer.

Joe Miller, of the Army Soldier and Biological Chemical Command, said the program is the latest technology for predicting the path of chemical plumes.

It was developed by Innovative Emergency Management of New Orleans under an Army contract, said meteorologist Michael Myirski, the Army's product manager at Aberdeen Proving Ground in Maryland.

Myirski said computer programmers started creating the new software in 1997, using information from meteorologists, physicists and mathematicians.

After it was created, the program was tested by IEM and the Army comparing actual data collected from the atmosphere to what the computer model predicts.

So far it has been placed in five of the eight chemical stockpile depots in the U.S., Myirski said. Madhu Beriwal, president of IEM, Inc., said her company is receiving about $32,000 per site to install the program and train employees how to use it.

It's a vast improvement over the program that had been used by the counties since the early 1990s, said Casey Beard, manager of Morrow County Emergency Operations.

In testing the old system, the operator would put in the number of the bunker where the release occurred, the type of chemical released and whether it was sent into the atmosphere a fire, explosion or some other means.

The program would add information from the weather station closest to the bunker to determine where and how far the plume would travel.

The model the software produced was a pie wedge shape, from the narrowest point at the accident scene, fanning out over areas that could be affected.

The problem is the wind across the high desert near the Columbia River frequently switches direction.

The new program, which emergency managers refer to as "puff," uses information from up to 19 weather stations surrounding the depot from Meachem to Boardman, plus data from the National Weather Service to make its predictions.

It also takes into account the terrain, Beard said, to give a much more accurate, detailed account of where the plume would travel.

Now, when the results are shown on the computer screen, emergency managers don't see a simple pie-shaped wedge.

The plume can turn toward a new direction or even reverse course within a few hours.

The model is color coded - red, orange and yellow - to show the amount of chemical exposure someone in a particular area would suffer. (Nobody wants to be in the red area during a chemical accident.)

And what emergencymanagers have learned by comparing the two programs is enough to send a chill up their spines.

Residents in the path of the plume have a good chance of escaping harm if they follow directions.

Depending on circumstances, some might be told to retreat to the most airtight portion of their homes and use duct tape and plastic to seal windows, doors and vents. Others could be asked to evacuate.

But while the public might be safe, the emergency crews rushing to set up mobile chemical decontamination units at hospitals and other areas near the depot might have been in danger if they relied on the old computer model, Beard said.

Beard cites one case where identical information was fed to both programs - and the results from the two computers were 120 degrees apart.

In some instances, crews could have been unwittingly sent directly into the plume, Beard said.

That's what makes 'puff' better and safer, Beard said.

But, he warned, it still is a computer model, and emergency workers will depend on mobile air monitors to make sure areas are safe.

Depot Commander Lt. Col. Fred Pellissier said that although the new equipment is much more sophisticated and accurate, residents in a 360 degree radius of the depot should still be prepared to protect themselves - regardless of what direction the plume is predicted to travel.

"My concern is people will think its absolutely accurate and it will give them a false sense of security," Pellissier said. "We need to err on the side of caution. It's better to be safe than sorry."

Actually, "puff" was created to err on the side of caution, Myirski said.

He said the Army doesn't make any claims about how accurate the computer program is, but it was programmed to exaggerate the size of a chemical release.

"It's designed to be wrong intentionally - to overestimate the risk to the community," Myirski said.

 

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