The World Meteorological Organization has certified a new world record for the longest lightning strike on record, a single bolt that measured 515 miles in length. The flash occurred on October 22, 2017, within a massive mesoscale convective system (MCS) that extended across the Central Plains of the United States. While the majority of the discharge occurred within the clouds, this single megaflash was responsible for 64 cloud-to-ground strikes, impacting areas from eastern Texas to Kansas City, Missouri. This record was recently identified through a reanalysis of data from the GOES East weather satellite, which allows for the detection of these enormous discharges, known as megaflashes, from over 22,000 miles above Earth’s surface.
The New World Record
The newly confirmed record for the longest lightning flash is now an astounding 515 miles (829 km). This single bolt of lightning was part of a large-scale thunderstorm complex and stretched horizontally from eastern Texas, across eastern Oklahoma and northwest Arkansas, and into southwest Missouri, near Kansas City. The World Meteorological Organization’s Committee on Weather and Climate Extremes confirmed this finding after a detailed review of satellite data.
What is a Megaflash?
Megaflashes are a term used by researchers to describe extremely long lightning discharges. While a typical lightning bolt is often less than 10 miles in length, megaflashes can extend for hundreds of miles. These events are rare and are typically associated with mesoscale convective systems (MCSs), which are horizontally extensive storm complexes. The new record highlights the significant distance lightning can travel within these storm systems, posing a potential hazard over a vast area.
Public Safety Implications
The discovery of this record-breaking megaflash underscores the importance of lightning safety. While the new record was a cloud-to-cloud discharge for much of its length, it produced numerous cloud-to-ground strikes along its path. This phenomenon, where lightning can strike far from the main thunderstorm cell, is a critical safety concern. The World Meteorological Organization recommends that individuals seek shelter in a substantial building or a fully enclosed vehicle when lightning is detected in the area, even if the storm appears distant.
The Top 10 Longest Lightning Strikes on Record
Based on World Meteorological Organization data, the top 10 longest lightning strikes on record are:
- 515 miles (829 km) over the Central United States on October 22, 2017, stretching from eastern Texas, across eastern Oklahoma and northwest Arkansas, to near Kansas City, Missouri.
- 477.2 miles (768 km) over the southern United States on April 29, 2020, from the central coast of Texas to southern Mississippi.
- 440.6 miles (709 km) over southern Brazil on October 31, 2018, stretching from the Atlantic coast into the edge of Argentina.
- 417.8 miles (672 km) over northern Argentina on March 4, 2019.
- 399.5 miles (643 km) over southern Brazil on December 16, 2019.
- 388.9 miles (626 km) over the southern United States on May 2, 2021.
- 375.3 miles (604 km) over northern Argentina on February 19, 2020.
- 365.1 miles (587 km) over the southern United States on May 17, 2018.
- 354.2 miles (570 km) over southern Brazil on January 21, 2020.
- 343.9 miles (553 km) over the southern United States on August 15, 2019.
Lightning Deaths and Fatalities
While lightning records for length and duration are a topic of scientific interest, the human impact of lightning strikes remains a serious concern. The World Meteorological Organization has also highlighted two other records related to lightning fatalities. In 1975, 21 people in Zimbabwe were killed by a single lightning bolt while seeking shelter in a hut. Another tragic event occurred in 1994 in Dronka, Egypt, where 469 people were killed when lightning struck oil tanks, causing a fire and a flood of burning oil.
For more information on lightning deaths and safety in the United States, you can visit our lightning fatalities page.