The World Meteorological Organization (WMO) has set two new world records for the longest distance and duration reported for lightning flashes, respectively, in Brazil and Argentina. New records for these “mega-lightnings,” verified with state-of-the-art satellite imaging technology, double previous values measured in the United States and France.
The findings have been published in Geophysical Research Letters, on the eve of World Lightning Safety Day, which is celebrated on June 28.
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 ± five mi) across parts of southern Brazil on October 31, 2018,” WMO said in a statement. This is a massive distance equivalent in comparison to the distance between Boston and Washington DC, or the city of London and the border of Switzerland in Europe, the researchers have explained.
The longest duration of a single lightning flash has been established at 16.73 seconds, from a mega-lighting flash that developed over Argentina in March 2019.
Previously, the largest record for a single lighting flash that covered the longer horizontal distances was a 321-km long lightning strike in June 2007 in Oklahoma. Both the old and new records used the same large-circle maximum distance methodology to measure the beam spread.
Furthermore, the previous record for a single lightning strike that lasted continuously was measured on August 30, 2012, when scientists detected a lighting strike that lasted 7.74 seconds, over Provence-Alpes-Cote d’Azur, in France.
“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,” explained Professor Randall Cerveny, chief rapporteur of Weather and Climate Extremes for WMO.
“This will provide valuable information for establishing limits to the scale of lightning – including megaflashes – for engineering, safety, and scientific concerns,” Cerveny said.
According to reports, lightning is a major hazard around the world. The recent findings highlight important public lightning safety concerns; the new data highlights the importance of safety measures to be taken in the presence of electrified clouds where lightning can travel long distances.
The 30-30 rule is something everyone should be acquainted with: if the time between flash and thunder is less than 30 seconds, go inside! And wait 30 minutes after the last observed flash to resume outdoor activities, reveals de WMO.
Since understanding lighting strikes is of great importance not only due to public safety but understanding how lighting could behave in distant worlds, scientists are pushing towards better instruments that can allow them to study lighting strikes more accurately.
Data gathered by ground-based Lightning Mapping Array networks is good but limited. Identifying megaflashes beyond current extremes would require a more developed mapping technology with larger observational domains, the WMO stressed.
This is precisely where space-based lightning mapping technology can take the next towards better understanding megaflahses. New instruments include the Geostationary Lightning Mappers (GLMs) on the R-series Geostationary Operational Environmental Satellites (GOES-16 and 17) that recorded the new lightning records and their orbiting counterparts from Europe (the Meteosat Third Generation (MTG) Lightning Imager) and China (FY-4 Lightning Mapping Imager), the WMO revealed.