In a recent milestone confirmed by the World Meteorological Organization (WMO), a truly gargantuan lightning flash has claimed the title of longest ever recorded. Scientists measured it at an astonishing 515 miles (829 km) — stretching from eastern Texas to near Kansas City, Missouri, a distance comparable to driving from Paris to Venice.
What is a Megaflash?
A megaflash refers to a single continuous, long-distance horizontal lightning discharge, capable of spawning hundreds of cloud-to-ground strikes across massive storm systems. These rare events typically occur in powerful Mesoscale Convective Systems (MCSs) — expansive thunderstorms often found in hotspots like North America’s Great Plains or parts of South America.
The record flash occurred on October 22, 2017, and blew past the previous record of around 477 miles (768 km) set in April 2020. That earlier strike also occurred in the southern U.S.
How It Was Measured
Researchers analyzed archival data from NOAA’s GOES‑16 satellite, part of a constellation that continuously monitors lightning globally. These satellites use optical lightning mappers, which—combined with ground‑based networks—allow high‑precision mapping of lightning events. This new data-driven re‑examination revealed the flash was nearly 38 miles longer than the previously recognized record and lasted just over 7 seconds.
Why It Matters
While the Gulf of Argentina–Uruguay system holds the record for longest duration (~17 s in June 2020), this U.S. megaflash sets the bar for horizontal distance Beyond the awe‑inspiring scale, scientists emphasize megaflashes carry real risks:
- They can travel far from their parent storm, sometimes producing “bolts from the blue” that strike under clear skies
- They pose hazards to aviation, wildfires, and public safety due to their unpredictability
Georgia Tech researcher Michael Peterson expressed optimism that as satellite technology expands globally, even more dramatic lightning extremes will be identified. Randall Cerveny of the WMO echoed this sentiment, suggesting many greater extremes likely await discovery.
Sign Up
