A newly confirmed lightning event has set the world record for the longest lightning flash ever recorded — stretching an astonishing 515 miles across the southern United States.
The “megaflash” occurred on October 22, 2017, but was only recently verified after meteorologists analyzed data from the GOES-16 weather satellite. The lightning bolt extended from eastern Texas to near Kansas City, Missouri, surpassing the previous record of 477 miles set in 2020.
What is a Megaflash?
A “megaflash” refers to a type of lightning bolt that covers an exceptionally large distance, typically over 100 kilometers (62 miles). These rare events form within large, long-lasting storm systems known as mesoscale convective systems. While rare, they pose unique hazards due to their reach far beyond the core of a storm.
How It Was Measured
Using satellite lightning mapping instruments, scientists were able to track the full path of the lightning bolt. The GOES-16 satellite, orbiting 22,000 miles above Earth, captured the full duration and range of the strike. Ground-based networks later confirmed 64 ground contacts originating from the same event.
Why It Matters
This megaflash underscores the unpredictable reach of lightning, which can strike far from the storm that produces it. These long-range bolts are sometimes referred to as “bolts from the gray,” appearing to come from clear skies but actually connecting to distant storm systems.
Beyond the science, the record shows the value of modern weather satellites in tracking extreme atmospheric phenomena and improving public safety during severe storms.
Previous Records
Previous Longest Flash: 477 miles (April 2020, in Brazil)
Longest Duration Flash: 17.1 seconds (June 2020, over Uruguay/Argentina)
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