The 1815 eruption of Mount Tambora is one of the greatest environmental disasters

The 1815 eruption of Mount Tambora is one of the greatest environmental disasters. The island's vegetation was completely decimated. Uprooted trees and pumice ash washed into the sea, forming rafts up to five kilometers (three miles) across. The British ships Fairlie and James Sibbald encountered massive pumice rafts around 3,600 kilometers (2,200 mi) west of Tambora between October 1 and 3. On April 23, dense ash clouds still shrouded the peak. Explosions stopped on July 15, however smoke emissions were detected as late as August 23. Four years after the event, flames and rumbling aftershocks were recorded.

On 10 April, a moderate-sized tsunami devastated the beaches of different Indonesian islands, reaching heights of up to 4 m (13 ft) near Sanggar around 22:00. Before midnight, a tsunami of 1-2 m (3-7 ft) in height was reported in Besuki, East Java, and one of 2 m (7 ft) in height in the Molucca Islands. The total number of fatalities is expected to be around 4,600.

The eruption column reached the stratosphere at a height of more than 43 kilometers (141,000 ft). The coarser ash particles settled out within one to two weeks of the eruptions, but the finer ash particles remained in the sky for months to years at altitudes of 10-30 km (33,000-98,000 ft). Longitudinal winds blow these small particles all over the world, causing visual phenomena. Sunsets and twilights were regularly witnessed in London between June 28 and July 2, 1815, and between September 3 and October 7, 1815. The dusk sky's radiance was often orange or red towards the horizon and purple or pink above.