The World Meteorological Organization (WMO) has established a new world record for the longest lightning flash - an incredible 829 km (515 miles) in a notorious storm hotspot in the United States of America.
The megaflash occurred in October 2017, during a major thunderstorm complex. It extended from eastern Texas to near Kansas City - equivalent to the distance between Paris and Venice in Europe. It would take a car about eight to nine hours and a commercial plane at least 90 minutes to cover that distance.
"Lightning is a source of wonder but also a major hazard that claims many lives around the world every year and is therefore one of the priorities for the international Early Warnings for All initiative. These new findings highlight important public safety concerns about electrified clouds which can produce flashes which travel extremely large distances and have a major impact on the aviation sector and can spark wildfires," said WMO Secretary-General Celeste Saulo.
WMO's Committee on Weather and Climate Extremes , which maintains official records of global, hemispheric and regional extremes, recognized the new record with the help of the latest satellite technologies. The findings were published in the Bulletin of the American Meteorological Society.
There is a margin of error of ± 8 km (5 mi) in the new record of 829 km (515 miles). It is 61 kilometers greater than the previous record, which covered a distance of 768 ± 8 km (477.2 ± 5 miles) across parts of the southern United States on 29 April 2020.
The new record lightning flash occurred in one of the hotspots for Mesoscale Convective System (MCS) thunderstorms, whose dynamics permit extraordinary megaflashes to occur - namely, the Great Plains in North America.
Both the previous and new record used the same maximum great circle distance methodology to measure flash extent. The 2017 event is notable in that it was one of the first storms where NOAA's newest Geostationary Operational Environmental Satellite (GOES-16) documented lightning 'megaflashes' - extremely long duration/distance lightning discharge events.
This particular flash was not identified in the original 2017 analysis of the storm but was discovered through a re-examination of the thunderstorm.
"This new record clearly demonstrates the incredible power of the natural environment. Additionally, WMO assessment of environmental extremes such as this lightning distance record testify to the significant scientific progress in observing, documenting and evaluating such events. It is likely that even greater extremes still exist, and that we will be able to observe them as additional high-quality lightning measurements accumulate over time," said Professor Randall Cerveny, rapporteur of Weather and Climate Extremes for WMO.
The WMO Archive of Weather and Climate Extremes maintains official records of the world, hemispheric and regional extreme records associated with a number of specific types of weather. Presently, the Archive lists extremes for temperature, pressure, rainfall, hail, wind, and lightning as well as two specific types of storms, tornadoes and tropical cyclones.
