News

The Hunga Tonga eruption sparked the highest-altitude lightning ever recorded

The plume from the 2022 eruption generated flashes up to 30 kilometers above sea level

A satellite image of the Hunga Tonga volcano when it erupted in 2022 with a large circle of smoke visible in the middle of blue water and other clouds.

The 2022 Hunga Tonga volcano eruption (shown in this image taken by a Japanese weather satellite) has added another superlative to its growing list of impressive stats: highest-altitude lightning flashes ever seen.

Japan Meteorology Agency via AP

By Skyler Ware

The Hunga Tonga volcano eruption continues to break records. Its latest? The highest altitudes that lightning has ever been known to start.

The plume from the eruption produced lightning flashes that kicked off 20 to 30 kilometers above sea level, researchers report in the June 28 Geophysical Research Letters.

The explosion of the underwater Hunga Tonga-Hunga Ha’apai volcano, in the island nation of Tonga, occurred in January 2022. The newly reported stratosphere-scraping flashes join the eruption’s growing list of standout stats, which include producing the greatest concentration of lightning ever detected and a plume so tall it touched space as well as generating a tsunami the size of the Statue of Liberty (SN: 12/13/22; SN: 8/29/22).

Volcanic lightning occurs when colliding ash particles make static electricity. To estimate the altitudes of the eruption’s flashes, volcanologist Alexa Van Eaton and colleagues analyzed data from ground-based lightning detection networks, infrared maps of lightning captured by satellites and satellite images of the plume.

Though some types of lightning can extend much higher into the atmosphere, a lightning flash doesn’t typically get started more than 20 kilometers above sea level. That’s because the air pressure is too low to form “leaders,” the channels of hot plasma that make up the lightning typically seen in thunderstorms.

The rising plume from the eruption may have raised the air pressure enough to create lightning at unusually high altitudes, says Van Eaton, of the U.S. Geological Survey’s Cascades Volcano Observatory in Vancouver, Wash.

In the Hunga Tonga eruption data, “we’re seeing stuff that we’ve never seen before,” says Jeff Lapierre, a study coauthor and principal lightning scientist at the company Advanced Environmental Monitoring, based in Germantown, Md. “Hunga has completely changed the way we think of how natural events can change the atmosphere, and the environment where we thought lightning could exist.”

Citations

A. Van Eaton et al. Lightning rings and gravity waves: Insights into the giant eruption plume from Tonga’s Hunga Volcano on 15 January 2022. Geophysical Research Letters. Vol. 50, June 28, 2023. doi: 10.1029/2022GL102341.

About Skyler Ware

Skyler Ware was the 2023 AAAS Mass Media Fellow with Science News. She has a Ph.D. in chemistry from Caltech, where she studied chemical reactions that use or create electricity.