‘Megaflash’ Lightning Records Certified by WMO

Geneva – The World Meteorological Organization (WMO) has established two new world records for so-called megaflashes of lightning, in notorious hotspots in North and South America.

In the southern United States, WMO’s Committee on Weather and Climate Extremes on Tuesday, officially recognized a single flash that covered a horizontal distance of 768 ± 8 km (477.2 ± 5 miles) on 29 April, 2020.

“This is equivalent to the distance between New York City and Columbus Ohio in the United States or between London and the German city of Hamburg,” said WMO in a press release.

The other record announced was for the greatest duration for a single lightning flash – of 17.102 ± 0.002 seconds from the flash – that developed continuously through a thunderstorm over Uruguay and northern Argentina, on 18 June 2020.

The new record for the longest detected megaflash distance is 60 kilometres more than the previous record, which was recorded with a distance of 709 ± 8 km (440.6 ± 5 mi) across parts of southern Brazil on 31 October 2018.

Both the previous and new record used the same maximum great circle distance methodology to measure flash extent, said WHO, meaning the shortest measurable distance between two points on a sphere.