On January 15, 2022, the Hunga Tonga-Hunga Ha’api (HTHH) underwater volcano erupted, producing the most powerful atmospheric explosion ever recorded. Now, a new study has found that it also generated the most intense lightning storm on record.
When the volcano erupted in the South Pacific, magma vaporized the seawater. This flung ash, gas, and 45 million metric tons of water vapor 58m into the sky. These conditions created “a supercharged thunderstorm, the likes of which we’ve never seen,” volcanologist Alexa Van Eaton explained.
The 11-hour eruption produced nearly 200,000 lightning flashes, with up to 2,615 flashes every minute. Two satellites recorded the electrical show.
Concentric rings of lightning
The satellite images revealed that the lightning did not strike in a random pattern but rather in concentric rings that coincided with each explosion. Previously, only single lightning rings have been witnessed, never multiples, and never this large.
“With this eruption, we discovered that volcanic plumes can create the conditions for lightning far beyond the realm of meteorological thunderstorms we’ve previously observed,” said Van Eaton. “It turns out that volcanic eruptions can create more extreme lightning than any other kind of storm on Earth.”
Data from the lightning storm has given scientists several insights into the eruption. For example, the eruption was previously thought to be a few hours long. The lightning data proved that it lasted for 11 hours.
Scientists split the eruption into four stages, clearly separated by different plume heights and lightning rates. The intensity of the lightning and eruptions were linked.
Over time, the lightning rings contracted and expanded. Never previously observed, this was caused by high-altitude turbulence. As the plumes drove ash, water vapor, and magmatic gas into the atmosphere, it created a ripple effect, and the lightning “surfed” the ripples. It is the first study to show that a strong volcanic plume can create its own weather system, with conditions that can maintain intense electrical activity.
Maps of the volcanic plume and lightning development on January 15, 2022. Image: Van Eaton et al. (2023), Geophysical Research Letters
A game changer
This type of eruption, known as phreatoplinian, only occurs when the magma from an underwater volcano erupts through the water in large quantities.
This eruption has been a game-changer for volcanologists, it is the first time that they have been able to observe and analyze a phreatoplinian with modern technology. Scientists hope that the information they have gathered will help with future volcanic hazard monitoring.
