On 5 April 1815, Mount Tambora began erupting on the Indonesian island of Sumbawa. It was the most explosive volcanic event in the historical record — a VEI 7, larger than Krakatoa, Vesuvius and Mount St Helens. Detonations were heard more than 1,000 km (620 miles) away. Villages were buried under ten feet of ash, their occupants found where they fell.
Then the ash went up, and stayed up.
Fine sulphate particles spread through the stratosphere and reflected sunlight back into space. Northern hemisphere temperatures fell by roughly 0.5 °C (1 °F) — a small number that lands catastrophically on a growing season. There was frost in June in New England, snow in July. Harvests failed across Europe. Americans called 1816 "Eighteen Hundred and Froze to Death". Somewhere around a million people starved.
That same summer, a group of English writers took a holiday at Lake Geneva, 12,344 km (7,670 miles) from the volcano. It rained without stopping. Mary Godwin, eighteen years old and not yet Mary Shelley, later described a famous dark day when the chickens went to roost at noon and candles were lit as though it were midnight.
Trapped indoors, Lord Byron proposed that they each write a ghost story.
For comparison:
- Tambora was VEI 7; Pinatubo in 1991 was a VEI 6 and still cooled the planet measurably
- The 1816 growing season failed across Europe, New England and parts of China and India
- Two monsters came out of that one contest: Mary's creature, and John Polidori's The Vampyre
- Polidori's story is the direct ancestor of Dracula — the modern vampire starts there
So the two most durable monsters in English fiction were both invented in the same room, in the same week, because a mountain on the other side of the world had made it too wet to go outside.
Nobody at Lake Geneva knew why the weather was so strange. The connection between Tambora and that summer would not be made for another century and a half.
The next time someone asks where Frankenstein came from, the answer starts with a mountain in Indonesia.