The Night Lake Nyos Breathed Out
One night in 1986, a lake in Cameroon released a silent cloud of gas that flowed into the valleys below.
What was reported
On the evening of 21 August 1986, Lake Nyos, a crater lake in north-western Cameroon, suddenly released a huge cloud of carbon dioxide. Heavier than air, it flowed down into the surrounding valleys, and about 1,700 people and thousands of animals died, many in their sleep.
Survivors reported a rumbling and a strange smell, and the lake's water turned red.
Explanations offered
Scientists found that carbon dioxide seeping up from magma had built up, dissolved in the lake's deep water, until something, perhaps a landslide, disturbed it and the gas burst out, an event called a limnic eruption. Since 2001, pipes have been releasing the gas safely, and nearby Lake Monoun is treated the same way.
- When
- 21 August 1986
- Where
- Lake Nyos, Northwest Region, Cameroon
- Witnesses
- Survivors, and the scientists who investigated
- Status
- Explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.