Some 10,000 died in the immediate catastrophe of raging pyroclastic flows and tsunami waves when Tambora erupted on the island of Sumbawa, Indonesia on April 10, 1815. Croplands were so devastated that starvation and disease raised the regional death toll to an estimated 70,000 people.
Perhaps the best eye-witness account of the early events comes from the Rajah of Sanggir, as recorded by Owen Philipps, a British Army lieutenant dispatched to Sumbawa with emergency food supplies:
About seven p.m. on the 10th April, three distinct columns of flame burst forth near the top of the Tomboro mountain (all of them apparently within the verge of the crater), and after ascending separately to a very great height, their tops united in the air in a troubled and confused manner. In a short time, the whole mountain next Sang’ir appeared like a body of liquid fire, extending itself in every direction. The fire and columns of flame continued to rage with unabated fury, until the darkness caused by the quantity of falling matter obscured it at about 8 p.m. Stones, at this time, fell very thick at Sang’ir; some of them as large as two fists, but generally not larger than walnuts. Between 9 and 10 p.m. ashes began to fall, and soon after a violent whirlwind ensued, which blew down nearly every house in the village of Sang’ir, carrying the ataps or roofs, and light parts away with it. In the part of Sang’ir adjoining Tomboro its effects were much more violent, tearing up by the roots the largest trees and carrying them into the air, together with men, horses, cattle, and whatever else came within its influence. The whirlwind lasted about an hour. No explosions were heard till the whirlwind had ceased, at about 11 a.m. From midnight till the evening of the 11th, they continued without intermission; after that time their violence moderated, and they were only heard at intervals, but the explosions did not cease entirely until the 15th July
Explosions were audible more than 1,000 miles away through the night of the 10th and into the 11th of April. Places within a 400-mile radius remained pitch black for one or two days, with residents reporting a dramatic lowering of air temperature. The eruption blasted aloft some 30 to 50 cubic kilometers of material — about 10 times more than Pinatubo’s output in 1991 and 50 times more than Mount St. Helens in 1980.
Tambora injected enough sulfate aerosol particles into the stratosphere to dim sunlight for more than a year, causing crop failures across Asia, Europe and North America. In June of 1816, frosts killed crops from Fairfield, Connecticut to Trenton, New Jersey. Snow fell in Albany, New York, and Dennysville, Maine.
The blast carved a caldera 6 kilometers [3.7 miles] across and 1,250 meters [4,100 feet] deep. Crater Lake in Oregon was created by an eruption of Tambora’s size about 7,700 years ago.