'Megaflash' measuring 829km sets new record for longest-ever lightning strike

The biggest ever lightning strike on record has been detected in the United States, spanning the equivalent distance between Sydney and Melbourne.

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.

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The megaflash occurred in a system of complex thunderstorms, and whilst it has captivated those in the meteorological world, the WMO has warned of the safety concerns surrounding such extreme weather events.

"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."

Around 100 people per year are struck by lightning in Australia, leading to between five to 10 deaths.

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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.

"These statistics demonstrate that there is no safe location below an electrified cloud that is producing megaflashes," Michael J. Peterson wrote in Earth Interactions in 2021.

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

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