The World Meteorological Organisation (WMO) confirmed the strike stretched 829 kilometres from eastern Texas to Kansas City.

It beat the previous record by 61 kilometres.

“Lightning is a source of wonder but also a major hazard that claims many lives around the world every year,” WMO Secretary-General Celeste Saulo said.

“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.”

A megaflash storm can send bolts hundreds of kilometres beyond where it originated, meaning people are totally unaware they could be at risk of being in the danger zone.

It can unleash five to seven ground strikes on average.

“Current lightning safety guidance is not always sufficient to mitigate megaflash hazards.”