New Study Offers Fresh Insights Into the Limits of Lightning Formation

Did you know volcanic eruptions can create their own weather, including lightning? Yet, volcanic lightning activity has received comparatively little study and is not well understood. Observations from a new study show just how surprising that activity can be.

I was thrilled to join with a world-class team of scientists to study the lightning activity associated with the January 2022 eruption of Tonga's Hunga Volcano. The research team featured scientists from NASA, the National Oceanic and Atmospheric Administration (NOAA), the U.S. Geological Survey (USGS), Los Alamos National Laboratory, and other respected institutions.

What we discovered was nothing short of incredible! This eruption produced lightning well beyond the range of any previous observations:

• As the plume of a volcano moves upward and outward, it can produce ever wider rings of lightning. This eruption produced the largest lightning rings ever observed (with a radius up to about 140km).
• At peak intensity, the eruption produced 2,615 flashes per minute, making it the most intense electrical storm ever detected by global networks.
• We also detected lightning in the volcanic plume at the highest altitudes ever observed (20-30km above sea level). Previous studies of thunderstorms have only detected lightning up to about 18km above sea level. And it was previously thought that 20-23km above sea level was about the upper limit of where lightning could initiate.

Our observations came from geostationary satellites operated by NOAA and by the Japan Meteorological Agency, as well as ground-based networks of radio lightning sensors. Among them was AEM's Earth Networks Total Lightning Network® (ENTLN), which is comprised of more than 1,800 ground-based sensors all around the globe.

Interestingly, during the course of the eruption, there was a five-hour period in which the upper-level plume cloud obscured satellite observations. However, our ground-based observations were able to fill in this blank with detailed information about the timing and intensity of the plume's formation. As a result, the study suggests the possibility of one day being able to monitor volcanic hazards with real-time lightning data.

I recently had the chance to join AEM's Talking With the Experts video podcast to share some of my thoughts about the study. It's a great place to pick up some additional insight into why this study is so groundbreaking.

Or, if you'd really like to dig into the science behind the discoveries, you can read our original paper, "Lightning rings and gravity waves: Insights into the giant eruption plume from Tonga's Hunga Volcano on 15 January 2022," which is published in the journal Geophysical Research Letters and licensed under CC BY 4.0.

Special thanks to my co-authors Alexa R. Van Eaton, Sonja A. Behnke, Chris Vagasky, Christopher J. Schultz, Michael Pavolonis, Kristopher Beka, and Konstantin Khlopenkov.