Satellite image of the volcano as it is today.
Source: Smithsonian Institution

200 years (and 17 days) ago, the Earth was visited by a terrifying slice of prehistoric oblivion. Mount Tambora sits on Sumbawa Island, a member of the Sunda Islands in Indonesia. Indonesia is a string of volcanic islands that lie along the southwestern edge of the Pacific Ring of Fire. It is home to 141 volcanoes, including the legendary Krakatau (better known as Krakatoa), and the supervolcano Toba that reportedly nearly drove humanity to extinction 74,000 years ago. Tambora made Mt. St. Helens look like a mouse fart. St. Helens spat out roughly 0.3 cubic miles of ash. Tambora released 38 cubic miles of ash. That’s enough to bury the entire state of New York, all 54,555 square miles of it, in 3.7 feet of ash. Its initial explosion was like an 800 megaton nuclear bomb. That’s 61,500 times more powerful than Hiroshima. Think about that for a second. The Hiroshima bomb made a major city disappear, seared people’s shadows into concrete and fused clothes to people’s skin. The Tambora eruption was 61,500 times more powerful than that.

A contemporary etching of the eruption.

Before 1815, Tambora hadn’t erupted in a thousand years. Many scientists believed it was extinct. Volcanism in Indonesia in general had been remarkably quiet for over a century. The country hadn’t had a major eruption since a relatively modest VEI 4 eruption (on a 0-8 scale, St. Helens was a 5, Tambora a 7) reportedly killed 3,000 people on the island of Halmahera and nearby islands in 1760. No eruption more powerful than that had happened there since the 1600’s. People simply stopped thinking about it. Beginning in 1812, however, things began to change. Residents heard rumbling coming from the mountain and periodic earthquakes occurred. Occasionally, a dark cloud wafted up from the mountain’s summit. For a while, nothing happened, but as the months passed, the earthquakes grew more frequent. Then, three years after the volcano awakened from its slumber, the unthinkable happened.

On April 5, 1815, Tambora exploded. Massive booms reverberated for hundreds of miles. People on Sumatra, 1600 miles away, heard what sounded like gunshots. British troops on nearby Java, which had been temporarily seized by the British to prevent it from falling to Napoleon after Indonesia’s colonizers, the Dutch, lost their homeland to the French, were mobilized because it was initially thought they were being attacked by naval cannon. Five days later, on the evening of April 10, the eruption intensified. Witnesses reported seeing three columns of ash and flame swell and merge together, towering high into the sky. Lava began to pour down the mountainside toward the villages below. Ash and pumice rained down and began to bury the landscape. Thick clouds of ash covered the sky as far away as Jakarta, nearly 800 miles away. People in Jakarta (then called Batavia) reported smelling a “nitrous” odor as a dark, ash-filled rain began to fall.

The pyroclastic flow from the Mt. Pinatubo eruption in 1991. The Tambora eruption was 14.5 times more powerful.
Source: PBS

Back on Sumbawa the situation was dire. Huge clouds of intensely hot rock, ash, and gas called pyroclastic flows surged down the mountain at very high speed, annihilating everything in their path, spreading out up to 12 miles from the summit. Pyroclastic flows are one of the volcano’s greatest killers. Much like a nuclear blast, exceptionally few of those caught in one live to tell about it. It was the pyroclastic flow that wiped out the people of Pompeii, many of them killed where they stood, frozen in horrifying repose before being entombed in ash for 1800 years before being excavated. Roughly 10,000 people met the same fate on Sumbawa. 38,000 more starved as all the island’s crops were wiped out. The entire island was stripped of vegetation. Everywhere within up to 370 miles of the summit was plunged into pitch darkness for up to two days.

A British military officer sent to the island by the Lieutenant-Governor of Java reported that bodies were strewn neglected by the sides of the roads. Virtually every survivor had been left homeless and they scrounged desperately for food. Water sources were contaminated by toxic ash and diarrhea was rampant, drastically increasing the death rate. It wasn’t much better on neighboring islands, as ashfall wiped out crops and created widespread famine. In those days, information traveled slowly, and with all the world’s major powers just coming out of major warfare, few resources were available to provide relief. On Sumbawa and surrounding islands, at least 71,000 people are believed to have died, making it the deadliest volcanic eruption in recorded history.

Temperature anomalies for the summer of 1816 in Europe.
Source: NOAA

The volcano’s effects were felt worldwide. The dust and ash from Tambora soared high into the atmosphere and was carried around the world by the jetstream, plunging the planet into a volcanic winter. Skies over England filled with dust and spectacular sunsets were reported across Europe and North America. Portions of central Europe experienced brown and red snow, tinged by the ash high in the atmosphere. August frosts were reported. Switzerland was particularly hard hit. Over the succeeding two years, the country’s average mortality rate doubled. It was so cold that an ice dam formed at the edge of Gietro Glacier, which then catastrophically collapsed in 1818, killing 44 people. Unusually heavy rains caused floods on Europe’s major rivers.

The eerie color of the sunset in this painting of the Chichester Canal in England by J.M.W Turner is believed to have been inspired by the atmospheric phenomena occurring across Europe and North America during the summer of 1816.

A persistent fog or mist shut out the sun across the United States and Canada. In 1816, throughout much of the northern hemisphere, summer never came. Portions of upstate New York reported sub-freezing temperatures throughout May. It snowed as far south as Pennsylvania in early June. Quebec City, Canada and the higher elevations of Vermont and New Hampshire received a foot of snow between June 6 and June 8. Lake and river ice was reported as far south as northwestern Pennsylvania throughout the summer. Frosts were reported as far south as Virginia on August 20/21. The Berkshire Hills of Massachusetts and Connecticut reported frost on August 23. Some areas recorded major frosts every month of the year. All of that from something that happened on the other side of the world. However, normal or even above normal summertime temperatures were reported at times, with the cold extremes happening at the end of wild temperature swings. Curiously, the Atlantic hurricane seasons of 1815 and 1816 appear to have been quite active, despite the record-cold summers (indeed, a hurricane struck the Florida Keys in early June, 1816 as snow was falling in New England). The 1817 season was much less active but it’s not clear if the aftereffects of the eruption had anything to do with that.

Sunset in Hong Kong nine months after the Pinatubo eruption in the Philippines, giving us a glimpse at how the skies over Europe and North America may have looked after the Tambora eruption. Note the low, dense veil of dust hanging over the water like smog.
Source: Wikipedia

Outside the Western Hemisphere, snow also fell on tropical Taiwan. Wintry precipitation was also reported in eastern China at latitudes comparable with the southeastern United States…in summer! Crops across China were wiped out. A severe monsoon season led to widespread devastating floods in China and India. Even when the winter finally abated, the weather remained miserable. Much of the northern hemisphere was mired by chilly weather and persistent rain and cloudiness.

The weather inspired a group of young authors and friends, Mary Godwin, John William Polidori, and Lord Byron, to challenge each other to see who could write the scariest story. Godwin, together with her future husband Percy Shelley, wrote Frankenstein, and Byron wrote a piece called A Fragment. Byron’s work inspired Polidori to write The Vampyre a few years later, which in turn inspired Bram Stoker’s Dracula as well as Alexandre Dumas’ The Count of Monte Cristo and is considered one of the founding works of the vampire genre and a hallmark of Gothic literature. Byron also wrote the poem Darkness about the persistent gloom. Oats to feed horses were so scarce that a German inventor, Karl Drais, came up with human-powered wheeled machines that were the precursors to the modern bicycle so that people could get around without horses.

Another Pinatubo sunset, this one was taken in Hawaii in the summer of 1991. Long after the sun had gone, the sky turned an intense red that lingered long after the usual twilight. This exact same phenomena was reported in Europe and the US after Tambora.
Source: Richard Fleet

Widespread crop failures brought on by the bitter cold of 1816 and 1817 had devastating effects on Europe and North America. Europe saw its worst famine of the 19th Century. Riots and looting were common as food prices soared. In the US, the famine was exacerbated by poor transportation networks (the Transcontinental Railroad was still nearly 40 years away), making it hard to import food. A typhus outbreak ravaged Ireland, killing 100,000 people. At least another 100,000 are believed to have died in Europe from the extreme conditions. In China, thousands starved. The exact death toll will likely never be known. Gillen D’Arcy Wood’s book Tambora: The Eruption that Changed the World paints a very dramatic picture of the dire conditions in some parts of China. “Famished corpses lay unmourned on the roads; mothers sold their children or killed them out of mercy; and human skeletons wandered the fields, feeding on white clay.” Local poets spoke of barren fields; never-ending rains; and desperate, starving people.

Modern researchers have questioned whether Tambora was the sole culprit of the upheavals of 1816 and 1817. Four VEI 4 eruptions had happened worldwide in the preceding three years and the Tambora eruption occurred during a period of low sunspot activity called the Dalton Minimum. All of these probably contributed to the severity of the climate impacts caused by the Tambora eruption.

Today, Tambora is quiet. The volcano hasn’t had an explosive eruption since 1880 but remains active. The area’s population has dramatically increased, and Tambora’s terrifying history earns it considerable attention from scientists. In recent years, periodic seismic activity around the mountain has been reported, just more reminders of the threat the volcano still poses.

The Tambora caldera as it looks today. The caldera was formed by the massive 1815 eruption.

Volcanic cataclysm of this magnitude is typically only found in ancient rocks and sediments of long-quiet craters, evidence of a hostile Earth whose ravages were wrought long before humans ever walked upon it. Today, we fear more the havoc we might wreak upon the Earth than the havoc it might wreak upon us. The pursuit of softer footprints and more conscientious stewardship is a noble one, but we should never forget how powerful this great planet is. It can uproot our peaceful existence and throw our society into turmoil at a moment’s notice. Events like Tambora, if nothing else, should remind us to appreciate today, because tomorrow isn’t guaranteed.