At 4:30am, Donna Willoya couldn’t sleep.
It was January 15, 2022, and the resident of Wasilla, Alaska had been having bouts of insomnia. She hopped out of bed, made tea, and stepped out onto her back deck for some fresh air. It was a beautiful, quiet night, she recalls, until suddenly, a thunderous explosion echoed through the dimly-lit sky.
“When we hear noises like that, it’s typically gunshots since there’s a lot of hunting in the area,” Willoya said. “But I’m from a family of hunters and very familiar with gunshots. This sound was clearly different—it was like unlike any I had ever heard.”
She had no idea what the boom was, so she shrugged it off and went back to bed. Later the next day, she saw the news report on TV: a massive submarine volcano 10,000 miles away in the South Pacific had erupted and sent audible shockwaves all the way to Alaska.
“I never thought something from Tonga would be heard on my deck,” she said.
The volcano, known as the Hunga Tonga–Hunga Haʻapai, had been restless for about a month before a perfect storm of events occurred: First, the volcano’s 150-meter-deep caldera collapsed. Then, seawater percolated through its exposed cracks and faults. Finally, magma rose up from the depths of the volcano and collided with the seawater at more than 1,000 degrees Celsius.
This resulted in one of the most intense volcanic eruption ever recorded, with some estimates suggesting that the explosion was hundreds of times stronger than Hiroshima. It not only sent atmospheric waves that circled the globe several times, but thrust more than a trillion grams of water vapor into the stratosphere and sent an ash cloud 35 miles into the mesosphere. Hurricane-force winds blew at the edge of space, while atmospheric pressure waves injected so much energy into the ocean below that meteotsunamis formed around the world.