Lake Nyos, 21 August 1986: The Night a Lake Exhaled
A crater lake in northwest Cameroon suddenly released a cloud of carbon dioxide that flowed downhill and killed about 1,746 people and thousands of cattle in their sleep. Scientists worked out what happened, and degassing pipes now vent the lake.
Sources G. W. Kling et al., 'The 1986 Lake Nyos gas disaster in Cameroon, West Africa', Science 236 (1987) 169, doi 10.1126/science.236.4798.169; USGS; Wikipedia, 'Lake Nyos disaster'
On the evening of 21 August 1986, people in villages below Lake Nyos, a deep crater lake in Cameroon’s Northwest Region, heard rumbling. A cloud of gas rose from the lake, rolled down the valleys at tens of kilometres an hour, and settled. Carbon dioxide is heavier than air and invisible. Within about 25 km, around 1,746 people and thousands of cattle suffocated, most in their homes.
Why it happened
The cause seemed mysterious at first: no fire, no lava. George Kling and colleagues showed in Science the next year that Nyos’s bottom water was saturated with carbon dioxide seeping from volcanic sources below. Some trigger, perhaps a landslide or cooling surface water, overturned the lake, and the gas came out of solution like a shaken soda. Scientists call it a limnic eruption; only two are known, both in Cameroon.
Afterwards
Since 2001, pipes have been venting gas from the lake’s depths to prevent another build-up.
Ledger status
Marked cited. A real, explained disaster. Map position is the lake, not any village or burial ground.
Sources
- Kling, G. W., et al. (1987), Science 236, 169 — doi:10.1126/science.236.4798.169
- Wikipedia, “Lake Nyos disaster” — en.wikipedia.org
Part of the World Ledger, batch 1. Original text; no images are used.
Evidence ledger
Each claim in this file, the source it rests on, and how well it holds up: 4 corroborated. What the labels mean.
| Claim | Source | Type · date | Status |
|---|---|---|---|
| A large cloud of CO2 erupted from Lake Nyos on 21 Aug 1986. | Kling et al., Science 1987 | scholarly · 1987 | corroborated |
| About 1,746 people and some 3,500 livestock died. | Wikipedia, citing official tallies | secondary | corroborated |
| The gas came from magmatic CO2 that had built up in the lake's deep water. | Kling et al. (1987) | scholarly · 1987 | corroborated |
| Degassing pipes installed from 2001 reduce the risk of a repeat. | USGS and project reports | official · 2001– | corroborated |
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