In October 2017, a remarkable meteorological event occurred when a massive bolt of lightning stretched across the sky from Dallas to Kansas City, officially recognized as the longest single flash ever recorded. This extraordinary megaflash measured a stunning 829 kilometers (about 515 miles) in length and lasted for 7.39 seconds, according to a recent study accepted by the Bureau of the American Meteorological Society. The research conducted by Michael Peterson, an applied physicist at Georgia Tech, utilized satellite data, highlighting the significance of advanced observation techniques in better understanding such phenomena.
Megaflashes are notable for their rarity, occurring in approximately 1 in every 1,000 thunderstorms across the Americas. Unlike typical lightning strikes, which last only a few microseconds and generally discharge energy to the ground, megaflashes are complex electrical discharges capable of lasting up to 100 milliseconds. This prolonged discharge allows the energy to infuse into trees, buildings, or other ground targets, increasing the risk of wildfires—an alarming consequence that underscores the power and reach of these natural phenomena.
The record-breaking megaflash of 2017 originated from a significant thunderstorm system that traversed the U.S. Midwest, delivering not only the longest recorded flash but also triggering at least 116 cloud-to-ground lightning strikes along its length. This highlights the megaflash’s ability to interconnect multiple lightning discharges that can pose serious risks in affected areas. The composite imagery compiled from 160 high-resolution National Weather Service radars showcasing various elevations enabled scientists to detect and analyze these flashes with unprecedented resolution.
Megaflash hotspots are typically found in regions like the U.S. Midwest and southeastern South America, where weather conditions create ideal environments for their formation. A previous record-holder, which spanned 709 kilometers over parts of Brazil and Argentina, continues to retain the record for duration—lasting an impressive 17 seconds. Researchers are keen on utilizing satellites positioned in geostationary orbits to identify and monitor these hotspots, aspiring to gain insights into the underlying mechanics that prompt such extensive lightning events.
The prevailing theory explaining megaflash formation involves the dynamics of thunderstorm updrafts, which carry various rain and ice particles to significant heights within the storm system. Each particle has the potential to acquire electrical charges, and as they collide, charge transfers occur, resulting in lightning formation. However, these particles are limited in how high they can ascend, generally not exceeding 11 kilometers, the upper boundary of Earth’s troposphere. When they reach this zenith and can’t rise further, they discharge laterally, leading to the phenomenon of megaflashes.
Understanding the intricacies behind the formation of megaflashes remains an active field of research. Peterson emphasizes their impact potential, stating that a single megaflash can affect large populations. This research not only aims to deepen scientific understanding but also seeks to improve safety measures for individuals impacted by such powerful lightning events. The quest to comprehend these extraordinary displays of nature continues, fostering greater appreciation for the complex interactions occurring within thunderstorm systems and the potential hazards they may present.
