A reappraisal of satellite data from 2017 revealed that a thunderstorm over the Great Plains produced a 515-mile lightning flash, the longest ever recorded. As science advances, researchers expect to uncover even longer flashes.
The “megaflash” streaked from northeast Texas to Kansas City during a major storm in October 2017. It measured 38 miles longer than the previous record holder, a 477-mile flash that stretched across the South in 2020.
Until recently, researchers primarily tracked lightning using antennas that picked up radio signals from flashes. It is possible to gauge the speed and size of a flash based on when disparate antennas register nearby lightning. But in the latest decade, satellite instruments have made it possible to more accurately track lightning over vast distances.
“Our weather satellites carry very exacting lightning detection equipment that we can use [to] document to the millisecond when a lightning flash starts and how far it travels,” said coauthor Randy Cerveny of Arizona State University. The new discovery, detailed in the Bulletin of the American Meteorological Society, was made by using new computational methods to reprocess existing satellite data.
Megaflashes typically arise from sprawling, long-lived thunderstorms and tend to strike the ground in several places, often far from their point of origin. “That’s why you should wait at least a half an hour after a thunderstorm passes before you go out and resume normal activities,” Cerveny said. “The storm that produces a lightning strike doesn’t have to be over the top of you.”
As the planet warms, increasingly hot and humid weather is fueling more lightning, particularly in the Far North.
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