Texas Tech University atmospheric scientist Eric Bruning is a member of the World Meteorological Organization's Committee on Weather and Climate Extremes, which has certified two record-breaking lightning flashes.
Eric Bruning Confirms Record-Breaking 'Megaflash' Lightning Events
Atmospheric Scientist Urges Awareness on International Lightning Safety Day.
With the summer thunderstorm season well underway, an international group of atmospheric scientists, including Texas Tech associate professor of GeosciencesEric Bruning, has certified two new world records for "megaflash" lightning events. The announcement from the World Meteorological Organization (WMO) coincides with International Lightning Safety Day on June 28, 2020.
According to the WMO study, the world's greatest distance for a single lightning flash took place on Oct. 31, 2018, and covered a horizontal distance of 440.6 miles across southern Brazil. The Brazil Megaflash event more than doubled the previous record for the longest detected distance of 199.5 miles across Oklahoma, measured June 20, 2007.
Satellite image of record extent, or distance, of lightning flash, which took place over Brazil on Oct. 31, 2018. Image courtesy of the World Meteorological Organization.
The WMO study also confirmed the world's greatest duration for a single lightning flash, which now stands at 16.73 seconds, measured from a flash over northern Argentina on March 4, 2019. It lasted more than twice as long as the record it broke: a single lightning flash that lasted 7.74 seconds on Aug. 30, 2012, over Provence-Alpes-Côte d'Azur, France.
Satellite image of record duration of lightning flash, which took place over Argentina on March 4, 2019. Image courtesy of the World Meteorological Organization.
"It was a pleasure to support this international team to validate the discovery of these flashes by Michael Peterson," Bruning said. "It is science working at its best when so many around the world contribute to making sense of these dramatic new flashes detected by this new instrument."
What do these four locations—southern Brazil, Oklahoma, northern Argentina and southwestern France—have in common?
Peterson, who works in the Space and Remote Sensing Group at Los Alamos National Laboratory, and Bruning are both members of the WMO's Committee on Weather and Climate Extremes and together noted all of these places are located in the midlatitudes.
"In the midlatitudes, thunderstorms can be organized by the change of winds with height in the atmosphere into large, long-lived thunderstorm complexes," Bruning says, "with a leading line of intense thunderstorms and a large area of steady precipitation behind the line of storms."
So, just how extraordinary are the record-breaking megaflashes?
"Most lightning flashes are about 5 to 6 miles wide inside a cloud," Bruning says. "The kinds of thunderstorm systems that produced the record flashes are common, and often have flashes of 60 miles in width that last 1 or 2 seconds in duration," Bruning says. "We've all seen these as channels that crawl along the underside of a cloud during steady rain after a thunderstorm passes. Basically, as a thunderstorm system gets bigger, the flashes also grow in length and duration. These are extraordinary examples where conditions were just right for them to span the whole thunderstorm complex."
Do these new records mean that lightning storms are getting worse, or that our ability to measure them is getting better?
"Our ability to measure lightning is getting better," Bruning says.
Thanks to satellite technology, recent advances in space-based lightning mapping offer the ability to measure flash extent and duration continuously over broad geospatial domains, according to the WMO.
These new instruments include the Geostationary Lightning Mappers on the R-series Geostationary Operational Environmental Satellites that recorded the new lighting records, and, expected to launch in late 2022, their orbiting counterparts from Europe and China. Bruning says a global constellation of lightning measurements will soon be a reality.
"The Geostationary Lightning Mapper is the first time we've been able to continuously map the extent and duration of connected lightning channels for a whole hemisphere of the Earth," Bruning says.
Before the use of satellites, lightning mapping data was collected by ground-based Lightning Mapping Array networks, which are still in use for data collection on a localized scale.