The lightning that sizzled down on Maryland from yesterday's thunderstorms had been under close watch for several hours by power managers at the Baltimore Gas and Electric Co.
Using a remarkable nationwide network of lightning-detection antennas and computer displays, they watched each strike as the storms brewed over south-central Pennsylvania before noon.
When the lightning began menacing BG&E;'s service territory in Harford, Baltimore and Carroll counties, utility officials put out a call for Dick Lepson.
"I was on the golf course and I got beeped by the people downtown," said Lepson, whose job as BG&E;'s superintendent of district operations required him to mobilize the company's work force to anticipate and respond to storm damage.
By the time he arrived at BG&E;'s storm center near Baltimore, activity displayed on the National Lightning Detection Network computers was intensifying and moving across the Maryland border.
Repair crews in five service districts in the storm's path were held past quitting time. More "trouble men" were called in early. The company's storm center was activated, and customer service personnel manned telephones, ready to take outage reports.
By 2 p.m., nearly 1,000 BG&E; personnel had been mobilized.
Between 2:15 and 3:15 p.m. alone, the detection system recorded nearly 1,200 lightning strikes in Central Maryland and around the Chesapeake's northern reaches. More than 79,000 BG&E; customers lost power.
But BG&E; officials believe the outages were shortened, and the costs reduced, thanks to the lightning-detection system's warning.
The system "gives us a lot more detail about where to mobilize," Lepson said. "Without it, what we probably would have to do is mobilize everything or wait" until the storm passed before calling in repair crews.
"It can cost tens of thousands of dollars just to have people sitting around waiting for something to happen," said Brian Deaver, an associate engineer for Distribution Systems Operations.
The National Lightning Detection Network measures and records nearly every bolt of lightning that strikes the United States -- some 10 million of them each year. Within 10 seconds of each strike, it is mapped to within 100 yards of its actual location and displayed as a dot on video maps across the country.
By "replaying" storms on the detection system's computer, utility managers also have pinpointed lightning strikes on long, rural transmission lines, and located damage that might otherwise have taken hours to find.
Joining the National Weather Service, the military, airlines and other users, 40 electric power companies across the United States now use the detection network to speed their repairs, anticipate generation needs, improve safety for repair workers and protect equipment.
Since it was installed for tests in 1984, the system has become BG&E;'s single most accurate and reliable device for tracking electrical storms, officials say.
Weather radar, public and private forecast services -- even cable TV's Weather Channel -- are still used. But radar tracks rain, Page said, not lightning, and forecasts can be wrong.
The lightning-detection network reports real, potentially damaging events as they happen.
The network was born in 1980 at the State University of New York in Albany, where research associate Ron Henderson and his colleagues were studying thunderstorms in the Albany area.
"We wanted to know how much lighting there was, the locations of lightning within thunderstorms, the intensity of lightning within storms, how many ground flashes there were," Henderson said.
Anyone can detect distant lightning in the static bursts that frequently overwhelm AM radio programming on summer evenings.
"That static you hear is actually information for us," Henderson said.
"From that [electromagnetic] radiation we can get a direction to where lightning occurred," he said. And by comparing the direction of a lightning flash from two or more widely spaced directional antennas, scientists can use triangulation to pinpoint the strike's location.
Scientists also learned to distinguish the signals emitted by cloud-to-cloud lightning from those of the more dangerous bolts that hit the ground. At SUNY, scientists developed the detector network concept, the computer software and displays, Henderson said.
In 1983, SUNY won funding from the Electric Power Research Institute and its network of lightning detectors was expanded to Florida. In 1984, BG&E; became the first utility to install the system for tests.
Finally, 3 1/2 years ago, SUNY created the first nationwide detection system by linking up to smaller networks operated in the West by the U.S. Bureau of Land Management and in the Midwest by the National Severe Storms Laboratory.
By next year, the network will be taken over as a fully commercial enterprise by GeoMet Data Services, of Tucson, Ariz., a spinoff of the detectors' manufacturer, Lightning Location and Protection Inc.
Today, 120 lightning detectors are operating nationwide, the nearest in Wilmington, Del.; State College, Pa.; and Charlottesville, Va.
Data are transmitted from each detector, via satellite, to computers in Albany, which process the information and relay it to terminals nationwide, all in 10 seconds or less.
Each strike appears on the computer screens as a cross-hair, which is quickly replaced by a colored "flare." The flares linger on the screen for up to an hour as visual clues to the extent, direction and speed of the storm.
The maps can be "zoomed" down from a coast-to-coast view to a span as small as six miles across, showing individual sections of BG&E;'s distribution system.
On a separate screen, the computer reports the latitude and longitude of each strike, the rate of strikes across the display, and the peak electrical current in each bolt, measured in kiloamperes.
All the data are stored on optical laser disks holding 1.2 billion characters of information. Five disks are filled each year and kept for playback and research, Henderson said.
Sometimes the lightning activity is astounding. "I've seen flash rates sustained at 26,000 flashes an hour nationwide," Henderson said.