How the Tonga Hunga volcano produced the most intense lightning ever seen

In phase three, the eruption continued at a lower intensity, with the height of the plume dropping to around 12–19 mi (20–30 km) high. “That’s still extraordinary,” Van Eaton says. Then there was an intriguing lull as the volcano apparently took a break, he explains before phase four saw the eruption lessen in ferocity over time.

“Being able to unravel this last gasp of the climate phase is really useful for those who need to forecast ash emissions and transport through the atmosphere,” says Van Eaton.

In the days that followed the eruption, the huge ash cloud produced by Hunga Tonga-Hunga Ha’apai was windswept nearly 1,860 miles (3,000 km) west of Australia. The ash can affect water supplies where it falls and hamper relief efforts.

Disruption due to volcanic ash is also extremely expensive for airlines. For example, in 2010 the eruption of the Icelandic volcano Eyjafjallajökull cost the aviation industry an estimated £1.1 billion (1.4 billion US dollars).

It is currently difficult to obtain reliable information on volcanic plumes at the start of an eruption, especially for remote submarine volcanoes. But the Hunga Tonga-Hunga Ha’apai data could help forecasters monitor and “forecast now” aviation-related hazards from explosive volcanism, including the development and movement of ash clouds.

Understanding this is vital, as scientists say an eruption on the scale of the Hunga Tonga-Hunga Ha’apai scale will likely occur again. And the threat is driving collaboration among researchers.

David Tappin, a volcano-triggered tsunami expert at the British Keyworth Geological Survey and a former chief geologist for the Kingdom of Tonga, cautions that the unexpected nature of the Hunga Tonga-Hunga Ha’apai eruption highlights the global danger of large volumes of volcanic eruptions is underestimated.

There are approximately 42 volcanoes around the world with the potential to erupt as spectacularly as Hunga Tonga-Hunga Ha’apaYoTappin says. This record-breaking eruption should serve as a wake-up call to prepare for more, but we are largely not ready for the effects of these facts, he says.

“This eruption has had such a far-reaching and global impact that we are all starting to reorganize the way we speak to each other,” adds Van Eaton. There were weeks of lower-level plumes before Hunga Tonga-Hunga Ha’apai “went wild,” she says. “This shows that even a fairly standard eruption can change course at any time, and there’s really no easy way to forecast or predict that.”

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