Shocking! Sparked by a major thunderstorm complex rumbling over the Great Plains, a single megaflash lightning bolt captured by NOAA’s GOES-16 satellite was recently certified by the World Meteorological Organization (WMO) as the world’s longest flash on record. The horizontal distance of the bolt stretched 515 miles (829 km) from eastern Texas to near Kansas City, Mo., when it flashed across the sky on October 22, 2017. 

Megaflash lightning is defined as a lightning bolt that reaches at least 62 miles (100 km) in length. By comparison, the average lightning bolt measures less than 10 miles (16 km) in length. Here's a fun fact you probably didn't know, most lightning is just an inch or so wide! 

This particular flash was not identified in the original 2017 analysis of the thunderstorm, but was discovered through a recent re-examination. It is nearly 38 miles (61 km) longer than the previous record-setting flash that lit up the southern U.S. on April 29, 2020, which was also verified through GOES-16 satellite imagery. That flash stretched 477 miles, from the central coast of Texas to southern Mississippi. It beat the prior record of 440.6 miles for a lightning strike across southern Brazil in 2018.

Image from NOAA’s GOES-16 satellite of the thunderstorm complex that produced the megaflash lightning bolt on October 22, 2017. [Image credit: NOAA/Cooperative Institute for Research in the Atmosphere (CIRA)]