April 10

Mount Tambora and the Year Without a Summer

Mount Tambora as it appears today via Volcano Weather

Today marks the anniversary of of the 1815 eruption of Mount Tambora on Sumbawa Island in Indonesia. It was one of the most powerful in recorded history, classified a a VEI-7 event, with four times the energy of the Krakatoa explosion. A moderate eruption had occurred on April 5, but intensified at around 7pm on the tenth turning the entire mountain into liquid fire. Sometime that evening the pyroclastic flow wiped out the village of Tambora. Eleven to twelve thousand were killed directly by the explosion, with another seventy to ninety thousand dying from the destruction of agriculture in the area by the fallout of volcanic ash. The eruption continued until July 15.

There were a number of odd effects. Prolonged and brilliantly colored sunsets were observed in England. In the eastern U. S. a frequent and long lasting fog that would not disperse with wind or rain was experienced. Hungary experienced brown snow, Italy red. But the strangest effect of the eruption was the Year Without a Summer, as 1816 became known.

Frosts occurred every month throughout the year. It snowed in June. Lake and river ice persisted as far south as Pennsylvania through July and August. Temperatures in the northeast fluctuated from normal (90s in the summer) to freezing within hours. Because of the weather's effect on crops, severe food shortages were common. Grain prices increased seven-fold.

The volcanic winter's effects were widespread in Europe, causing the worst famine of the 19th century there. The famine in Ireland precipitated a major typhus epidemic. In China the eruption disrupted the monsoon season, causing disastrous floods. In India the delayed summer rains aggravated the spread of cholera, which reached epidemic proportions as far afield as Moscow.