The world's longest lightning flash, in terms of distance traveled and
duration, was recorded from space. This record has been confirmed by the WMO
World Meteorological Organization.
Previously, one of the lightning flashes occurred in the southern US in
April 2020 with a length of about 768 kilometers. This record is longer than
the previous record that occurred in Brazil in 2018.
The next lightning flash was measured in June 2020. It crossed the
Uruguay-Argentina border, and lasted 17 seconds, longer than any other flash
ever detected.
"We now have clear evidence that a single lightning event can last as long
as 17 seconds," said Randall Cerveny of Arizona State University.
"This is important for scientists, because it improves our understanding of
lightning dynamics: how, where, and most importantly, why lightning occurs
the way it does."
Flashes are seen in thunderstorm hotspots, in North America's Great Plains
and the Río de la Plata basin in South America.
The geography of the area makes both regions vulnerable to relatively large
convection systems, which can cause individual thunderstorms to combine into
a large weather system that triggers extreme lightning strikes.
Flashes extending across the southern US would be difficult to measure with
conventional ground-based equipment, so meteorologists turned to lightning
maps on geostationary satellites, which have a much wider field of view.
"We've had this type of lightning detection and mapping equipment in orbit
for several years, and we're learning a lot more about big flashes," Cerveny
said.
Although both flashes were detected in 2020, it is only now that WMO
certifies the event as the longest-range and longest-lasting lightning bolt
on record.
According to Graeme Marlton at the Met Office, UK, there is a long process
of instrument re-checking, observation and cross-check verification from a
panel of experts before the event can be recorded as a world record
lightning strike.
These two flashes that occurred in 2020 may indicate that the lightning is
becoming more extreme, but it could also be that the imaging capabilities
are becoming more sophisticated that allowed both records to be broken.
"It is only after a few years of these extreme events being recorded that we
can assess whether they are becoming more common," Marlton said. However,
climate change appears to be increasing the frequency of lightning across
Earth.
This measured lightning strike did not make contact with the ground.
However, its length and duration is still an important reminder of how far
lightning can strike from its host region.
"Every time you hear thunder, you should find a place that is safe from the
lightning, such as a large building or fully enclosed metal-clad vehicle,"
he advises.
