A Volcanic Eruption Sparked the Highest Lightning Ever Seen
By: Mia Wang
In 2022, an underwater volcano in Tonga, a South Pacific Island, erupted and blasted a plume of water vapor and ash into Earth's stratosphere. The eruption generated powerful shockwaves that triggered an enormous tsunami nearly four weeks later.
Volcanic eruptions rarely spew much water into the stratosphere. "In the 18 years that NASA has been taking measurements, only two other eruptions – the 2008 Kasatochi event in Alaska and the 2015 Calbuco eruption in Chile – sent appreciable amounts of water vapor to such high altitudes." (NASA) Even though these two eruptions sent a good amount of water into the stratosphere, the water dissipated quickly. In contrast, the water vapor launched from the Tonga explosion remained there for a few years, setting a new record for the highest volcano plume. Because it sent so much water vapor into the stratosphere, the water vapor effectively trapped heat in our atmosphere, in turn, heating our Earth.
Recently, scientists have discovered that the eruption also triggered the most intense lightning storm ever recorded. Storms typically form in the troposphere, but the plume from the eruption generated lightning up in the stratosphere, higher than planes fly.
Lightning is usually generated inside storm clouds but can also form inside a volcano's plume, made of bits of ash, gas, and dust. When rubbed together, these little particles create static electricity. Once enough electricity has been collected, lightning flashes.
Scientists used different types of data to determine the lightning's height, including measuring radio waves created by the lightning. Scientists also used satellite images of the eruption used “pixel mapping to obtain the timing, location, flash area, and optical brightness of lightning.” (Advancing Earth and Space Sciences). The third way was by measuring infrared light from the flashes.
This data collection showed that lightning's height was 20 kilometers above sea level. This is very peculiar because, typically, lightning doesn't start that high because the air pressure is too low for lightning to form. Lightning usually starts at 2-3 kilometers above sea level.
The Tonga volcano eruption broke many records -- it was the largest volcano since 1991, and its eruption triggered the most intense lightning in history, triggering more lightning bolts than in any other natural event. The event has changed how we think natural events can impact our Earth and atmosphere.