700-Kilometer Megaflash Sets New Lightning World Record


Katy Evans

Managing Editor

clockJun 26 2020, 16:55 UTC

Lightning over Porto Alegre, Brazil. Thiago B Trevisan/Shutterstock 

The World Meteorological Organization (WMO) has confirmed a phenomenal lightning strike that split the sky in Brazil in 2018 has set the new world record for the longest lightning bolt.

Reaching 709 kilometers (440 miles) long – about the distance from New York to Charleston, WV – the “world’s greatest extent for a single lightning flash” was recorded on October 31, 2018, in southern Brazil, the WMO’s Committee on Weather and Climate Extremes announced.  


That wasn't the only flashy record-breaker the UN’s weather agency announced though. The record for the longest duration of a lightning flash got smashed too, thanks to a 16.7-second-long “megaflash” that occurred over northern Argentina on March 4, 2019.

Both new records have wiped the floor with the previous record-holders by more than double. The previous distance record was 321 kilometers (199 miles) recorded in Oklahoma in 2007, and the duration record was a mere 7.74 seconds over Provence-Alpes-Côte d'Azur, France, in August 2012.

“These are extraordinary records from single lightning flash events,” said Professor Randall Cerveny, chief rapporteur of Weather and Climate Extremes for WMO, and co-author of the study confirming these findings in Geophysical Research Letters. “Environmental extremes are living measurements of what nature is capable, as well as scientific progress in being able to make such assessments. It is likely that even greater extremes still exist, and that we will be able to observe them as lightning detection technology improves.”

Satellite image of record extent of lightning flash, Brazil, October 31, 2018. WMO

Previously, lightning was tracked using data from ground-based sensors called Lightning Mapping Array networks, which detect radio waves. However, lightning scientists acknowledged there was an upper limit to the scale of lightning that could be traced using these, and tracking more extreme lightning would require a scale-up of the technology.

In 2016, the US National Oceanic and Atmospheric Administration (NOAA) launched the world’s first lightning-mapping satellite to operate in geostationary orbit, tracking Earth’s weather from 36,000 kilometers (22,300 miles) above us. This means that not only can we monitor Earth's weather 24/7, but as increased lightning activity is usually a good indicator of tropical cyclones and thunderstorms, forecasters now get a more accurate idea of what's coming.

It was this lightning-mapping tool, operating on the Geostationary Operational Environmental Satellites (GOES), that recorded the two new records.

Satellite image of record duration of a lightning flash, Argentina, March 4, 2019. WMO

There are many different types of lightning. Lightning always accompanies thunder and they both happen at the same time, but as light travels faster you often see the lightning before you hear the thunder. Most lightning starts within a thunder cloud and then either stays in the cloud or travels through air, either to another cloud or to eventually hit the ground. Both record-breaking flashes occurred from cloud to cloud, without touching the ground, but why were they so powerful? 

There are two hotspots in the Americas where mesoscale convection systems – thunderstorms that combine into large clusters, or "superstorms" – form: the Great Plains in North America and La Plata basin in South America. These superstorms occur on a scale that allows for extraordinary megaflashes. Now that we have the technology to monitor and observe these megaflashes, it's highly unlikely these new records will stand for long though.