"Maps" Help Reveal How Lightning Strikes

Craig Miller
National Geographic Channel
September 25, 2002

During the late New Mexico summer and early fall, afternoon clouds gather over the mountain peaks. The rising desert heat pushes them into vertical towers until they burst forth into storms that produce fleeting, torrential rains, flash floods and remarkable displays of lightning. This is when Bill Rison, a lightning researcher, heads for the hills.

For the past 18 years Rison, a professor of electrical engineering at New Mexico Tech, Socorro, has been chasing his elusive subject as part of the lightning research team.

"There is much that we still don't know about lightning," says Rison. "We just don't understand what it is that initiates lightning in thunderstorms." Lightning also occurs without thunderstorms, adds Rison, such as during volcanic eruptions and in the smoke-laden air above wildfires.

High-speed video reveals that lightning begins with a dim light coming down from the cloud, then when the light has almost reached the ground a luminous spark seems to travel from the ground up. "We have no idea what features on the ground initiate the 'spark' that causes lightning to strike at that particular spot."

Researchers also do not know what causes the jagged structure of lightning.

Lightning Fatalities

The almost daily light shows above New Mexico are as dangerous as they are dazzling. Per capita, the state has the highest incidence of lightning fatalities in the nation. Highway workers are especially vulnerable.

But Patricia Stribling wasn't paving a highway. She had just come out of the Post Office in Corrales, on a spring day in 1986, and returned to her car, which was parked right next to the flagpole.

"Then, just all of a sudden was…this light that was like being in an arc welder's light and…this horrendous sound," says Patricia Stribling.

Stribling was probably caught in the periphery of a bolt that hit the aluminum flagpole. She'll never be certain exactly what happened. "But mostly I remember that light because I had seen arc welder light and it was the most blue, white intense light that I'd ever seen," she said.

Rison has seen that light many times over the years and aspects of it remain mysterious, even to the experts. After 45 years, Rison's colleague Charles Moore is still surprised by new findings.

Continued on Next Page >>




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