In short
On April 5, 1815, Mount Tambora in Indonesia exploded with such force that it ejected 150 cubic kilometers of rock, ash, and gas into the atmosphere—the largest volcanic eruption in recorded history. The blast killed around 71,000 people directly and indirectly, darkened skies across the globe, and triggered crop failures that led to widespread famine the following year.
How it unfolded.
The five-minute version
What actually happened.
Mount Tambora, or Tomboro, is an active stratovolcano in West Nusa Tenggara, Indonesia. Located on Sumbawa in the Lesser Sunda Islands, volcanism is the result of subduction zones. The 1815 eruption was the largest in recorded history, erupting up to 150 cubic kilometers of volcanic material, making it a VEI-7 on the Volcanic Explosivity Index. This caused the summer of 1816 to become known as the "Year Without a Summer" due to global cooling from the eruption.
As it was happening
12 voices, 637 days.
One beat at a time. Click any dot on the timeline to jump, press play for autoplay, or use the arrow keys to step.
Main eruption
Tambora explodes violently at dawn, ejecting an ash column to 43 km altitude. The blast is heard on Timor, over 4,000 km away.
Voices from this moment (1)
Main eruption
Apr 5
“Tambora explodes violently at dawn, ejecting an ash column…”
As it was happening
12 voices, 637 days.
Day 0 · April 5, 1815
Main eruption
Tambora explodes violently at dawn, ejecting an ash column to 43 km altitude. The blast is heard on Timor, over 4,000 km away.
“Tambora explodes violently at dawn, ejecting an ash column…”
- Main eruption, Apr 5
Day 1 · April 6, 1815
Pyroclastic flows and tsunami
Pyroclastic flows race down the mountain's slopes at high speed; tsunamis generated by the eruption strike nearby coasts, killing thousands.
“The explosion was heard distinctly in Sumatra, at the…”
- Official report to the East India Company, Java, 1815, Apr 12
“We could not see the bow from the stern.”
- Synthesized from period accounts - Dutch maritime logs and eye-witness testimony, 1815, Apr 15
“Pyroclastic flows race down the mountain's slopes at high…”
- Pyroclastic flows and tsunami, Apr 6
Day 57 · June 1, 1815
Global ash veil reaches peak
Volcanic aerosols encircle the Earth, reducing solar radiation and initiating a sharp drop in global temperatures.
“The darkness at noon was so complete that candles were…”
- Zoological Researches in Java and the Neighbouring Islands, 1824, Jun 15
“FR: 'Les récoltes ont péri, la terre est couverte de…”
- Synthesized from period accounts - Dutch colonial correspondence, 1815, Sep 1
“Volcanic aerosols encircle the Earth, reducing solar…”
- Global ash veil reaches peak, Jun 1
Day 271 · January 1, 1816
The Year Without a Summer begins
Winter and spring conditions persist into summer across the Northern Hemisphere; frost and snow reported in June in New England and Europe.
“The mountain burst open and fire shot forth.”
- Synthesized from period accounts - Malay Annals and merchant logs, 1815-1816, Mar 1
“Winter and spring conditions persist into summer across the…”
- The Year Without a Summer begins, Jan 1
Day 423 · June 1, 1816
Crop failures widespread
Failed harvests across Europe, North America, and Asia trigger food shortages and steep grain prices. India and China also report severe drought and famine.
“Failed harvests across Europe, North America, and Asia…”
- Crop failures widespread, Jun 1
Day 636 · December 31, 1816
Famine and unrest peak
By year's end, Europe and North America have endured the costliest weather-driven famine of the 19th century. Bread riots erupt in multiple countries.
“By year's end, Europe and North America have endured the…”
- Famine and unrest peak, Dec 31
Day 637 · January 1, 1817
Recovery begins
Global temperatures stabilize and begin to recover. Harvests improve, though regional food crises persist into 1817.
“Global temperatures stabilize and begin to recover.”
- Recovery begins, Jan 1
The numbers.
6 numbers that anchor the scale.
By the numbers
The countable parts.
VEI rating
0 (highest on the scale)
Material ejected
~0 cubic kilometers
Direct and indirect deaths
~0
Height of eruption column
~0 kilometers
Global temperature drop
0.0–0.7°C in 1816
Deaths on Sumbawa
~0 from blast, pyroclastic flow, and tsunami
Captured in time.
Captured before it changed
The web as it looked, the day it happened.
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Sources & citations.
Sources
Where this came from.
Every claim on this page traces to a public, license-clean source. We don't asterisk well.
Wikipedia
1 source- 1.Mount Tambora
en.wikipedia.org