The average bolt of lightning is less than 10 miles long, but this was no ordinary bolt of lightning. The World Meteorological Organization says an epic "megaflash" during a severe storm in 2017 stretched 515 miles from eastern Texas to the Kansas City, Missouri, area, covering in seconds a distance that would take a car more than eight hours and a commercial plane at least 90 minutes. That's a record, beating a 477-mile megaflash over Mississippi, Louisiana, and Texas. The WMO says the megaflash was discovered through a reexamination of the Oct. 22, 2017, thunderstorm with new methods.
The lightning bolt traveled horizontally for hundreds of miles through layers of clouds in the massive storm system, likely shooting off ground-striking bolts along the way, CNN reports. Randall Cerveny, a professor of geographical sciences at Arizona State University, says megaflashes are an "incredibly strange phenomenon," NBC News reports. "We only discovered them 10 years ago, when we could use a particular set of technologies to detect the start and end locations of lightning events," says Cerveny, a member of the WMO committee that confirmed the record. Scientists believe the megaflashes occur only in a few parts of the world where conditions are right—including the Great Plains.
"Flashes at this extreme scale always existed, and are now becoming identifiable as our detection capabilities and data processing methods improve," researchers wrote in a study published Thursday in the Bulletin of the American Meteorological Society. Lead author Michael Peterson says megaflashes can be a "worst-case lightning scenario," causing wildfires or damage hundreds of miles from a storm's core, CNN reports. "You don't see where they come from. You only see where they strike," Peterson says.