Lightning ‘megaflash’ stretching over 700km and another lasting 16.7 seconds break distance, duration records
Megaflashes are far-larger lightning strikes that reach hundreds of kilometers in length. The new records, verified with new satellite lightning imagery technology, are more than double the previous values
New records for extreme lightning bursts or ‘megaflashes’ have been created, more than doubling the size and duration of the previous record flashes. The two new world records are for the longest reported distance and the longest reported duration for a single lightning flash in Brazil and Argentina, respectively.
The records for megaflashes — far-larger lightning flashes that reach hundreds of kilometers in length — were verified with new satellite lightning imagery technology, and surpass the previous values measured in the US and France, says the World Meteorological Organization (WMO).
According to the scientists, the flash that stretched more than 700 kilometers (400 miles) across southern Brazil on October 31, 2018, was equivalent to the distance between Boston and Washington, DC, or between London and the border of Switzerland near Basel. Further, the flash that developed continuously over northern Argentina on March 4, 2019, lasted a massive 16.73 seconds. The findings have been published by the American Geophysical Union’s Geophysical Research Letters ahead of International Lightning Safety Day on June 28.
The previous record for the longest detected distance for a single lightning flash was for 321 km (199.5 miles) on June 20, 2007, across the US state of Oklahoma. The previous record for the duration was for a single lightning flash that lasted continuously for just 7.74 seconds on August 30, 2012, over Provence-Alpes-Côte d'Azur, France.
“WMO’s Committee on Weather and Climate Extremes, which maintains official records of global, hemispheric and regional extremes, found that the world’s greatest extent for a single lightning flash is a single flash that covered a horizontal distance of 709 ± 8 km (440.6 ± 5 mi) across parts of southern Brazil on October 31, 2018. The greatest duration for a single lightning flash is 16.73 seconds from a flash that developed continuously over northern Argentina on March 4, 2019,” the findings state. It adds, “The two megaflash events exceed global lightning extremes (horizontal length, duration) by a factor of two.”
The WMO Archive of Weather and Climate Extremes maintains official records of the world, hemispheric, and regional extreme records associated with many specific types of weather. Currently, the Archive lists extremes for temperature, pressure, rainfall, hail, wind, and lightning as well as two specific types of storms, tornadoes, and tropical cyclones.
Lightning is a major hazard that claims many lives every year. According to the research team, the findings highlight important public lightning safety concerns for electrified clouds where flashes can travel extremely large distances.
“These are extraordinary records from single lightning flash events. Environmental extremes are living measurements of what nature is capable, as well as scientific progress in being able to make such assessments. It is likely that even greater extremes still exist, and that we will be able to observe them as lightning detection technology improves,” says Professor Randall Cerveny, chief rapporteur of Weather and Climate Extremes for WMO, in the report. He emphasizes that the technology could help scientists better understand the whole science of lightning, and potentially save lives. “This will provide valuable information for establishing limits to the scale of lightning, including megaflashes, for engineering, safety, and scientific concerns,” says Cerveny.
The previous assessments that established the flash duration and extent records used data collected by ground-based Lightning Mapping Array (LMA) networks. Many lightning scientists acknowledged that there are upper limits for the scale of lightning that could be observed by any existing LMA. Identifying megaflashes beyond these extremes would require a lightning mapping technology with a larger observation domain.
Recent advances in space-based lightning mapping give scientists the ability to measure flash extent and duration continuously over broad geospatial domains. The new record-breaking strikes were recorded by equipment carried on the Geostationary Operational Environmental Satellites (GOES-16 and 17), and their orbiting counterparts from Europe (the Meteosat Third Generation (MTG) Lightning Imager) and China (FY-4 Lightning Mapping Imager). “This dramatic augmentation of our space-based remote sensing capabilities has allowed the detection of previously unobserved extremes in lightning occurrence, known as megaflashes,” says lead author and evaluation committee member Michael J Peterson from the Space and Remote Sensing Group (ISR-2) of Los Alamos National Laboratory, US.