
The crater at the top of the peak (called a caldera) began to rumble. At one point, a dark cloud formed above the volcano.
The volcano had been dormant for hundreds and hundreds of years, but it looked like it was waking up. Sure enough, on this date in 1815, an eruption spit out ash and gas.
The people of the nearby village of Tambora—and the people of the island of Sumbawa—and even the people of the other Indonesian islands, hundreds of miles away—heard thunderous booms. Ash started to fall from the skies.
Five days later, the largest volcanic eruption in history shook Tambora-the- mountain and, sadly, eliminated Tambora-the-village.
The Tambora eruption was TEN TIMES more powerful than the more famous Krakatoa eruption of 1883!
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This chart compares the eruption of Tambora to three smaller but more famous eruptions: Mt. Vesuvius, which destroyed Pompeii; Krakatoa, also in Indonesia; and Mount St. Helens, in Washington state. |

And the ash fell. And fell. And fell some more.
Some of the tiniest particles of ash stayed high up in the atmosphere, and blew around in the wind currents, and blocked the sun. The next year, 1816, was called “The Year Without a Summer” in the United States and Europe, because the volcanic eruption put so much ash and sulfur into the atmosphere that more sunshine was reflected away from the Earth, back into space, and the temperatures dropped all over the world. This phenomenon is called a volcanic winter—and during this one, it snowed in Boston, Massachusetts, in July!
Like any global climate change, this volcanic winter caused hardship and death as some crops failed, some livestock died, and thousands of people starved.
Tambora is now called the Pompeii of the East because archaeologists have begun to excavate the lost culture of Tambora that had been buried by pyroclastic flows. The team of scientists had to cut through a “pavement” of pumice and hardened ash about 10 feet (3 m) thick!

Also on this date: