The eruption of the undersea volcano in the South Pacific on Saturday was so loud, many Tongans could not hear and had to signal to each other while evacuating, according to an eyewitness.

"The first explosion…our ears were ringing and we couldn’t even hear each other, so all we do is pointing to our families to get up, get ready to run," Marian Kupu, a journalist on Tonga, told Reuters.

This satellite images provided by Maxar Technologies shows an overview of Hunga Tonga Hunga Ha'apai volcano in Tonga on Jan. 6. (Satellite image ©2022 Maxar Technologies via AP) (Satellite image ©2022 Maxar Technologies via AP)

The eruption was 600 times more powerful than the atomic bomb dropped on Hiroshima, according to scientists. NPR reported that the eruption was likely one of the loudest events to occur on the planet in 100 years and could be heard in Alaska.

WHY ERUPTION WAS SO BIG AND WHAT'S NEXT

"This might be the loudest eruption since Krakatau in 1883," Michael Poland, a geophysicist with the U.S. Geological Survey, told NPR, referring to the Indonesian volcano eruption.

The first flights carrying fresh water and other aid to Tonga finally arrived Thursday after the Pacific nation’s main airport runway was cleared of ash.

This satellite image provided by Maxar Technologies shows an overview of Hunga Tonga Hunga Ha'apai volcano in Tonga on April 10. (Satellite image ©2022 Maxar Technologies via AP) (Satellite image ©2022 Maxar Technologies via AP)

New Zealand and Australia each sent military transport planes that were carrying water containers, kits for temporary shelters, generators, hygiene supplies and communications equipment. The Australian plane also had a special sweeper to help keep the runway clear.

GET THE FOX NEWS APP

Rear Admiral James Gilmour, the commander of New Zealand’s Joint Forces, said there had been a "mammoth effort" by Tongan troops "to clear that runway by hand. And they’ve achieved that this afternoon."

Fox News' David Aaro and the Associated Press contributed to this report