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The Deadly Lake Nyos Disaster In Africa

Where is Lake Nyos?

Lake Nyos is a crater lake in the Northwest Region of Cameroon in Africa, located about 315 km (196mi) northwest of Yaoundé, the capital. 

Lake Nyos in Africa

Lake Nyos Eruption 

A limnic eruption at Lake Nyos erupted on August 21, 1986  which killed 1,746 people and 3,500 livestock. The Lake was located in northwestern Cameroon. Lake Nyos sits high in a volcanic plain bounded by the Cameroon line of volcanoes, which stretches into the Gulf of Guinea. The lake itself fills a circular maar, formed when groundwater meets hot lava or magma and explodes. The hole from the eruption eventually fills the water, forming a crater lake.

In August 1986, a cloud of magmatic carbon dioxide gas emerged from the bed of Lake Nyos. It was announced by a small explosion that residents near the lake described as being like distant thunder, but it was otherwise unannounced by anything else apart from a foul odor. What triggered the outgassing  is not yet known. Most geologists suspect a landslide, but others believe a small volcanic eruption may have occurred on the bed of the lake. There is also a possibility that cool rainwater falling on one side of the lake triggered the overturn. 

The normal blue waters of the lake turned red after the outgassing which was caused by iron-rich water from the deep rising to the surface and being oxidized by the air. The level of the lake dropped by about a meter and trees near the lake were knocked down. It is a possibility that other volcanic gasses were released, as some survivors reported the smell of gunpowder or rotten eggs, which indicates that sulfur dioxide and hydrogen sulfide were present at concentrations above their odor thresholds. 

Effects On The Survivors And The Victims 

Despite the dangers of living so close to active volcanoes and dangerous lakes, roughly 10,000 people populate the area. The soil on and around the old volcano is rich and fertile, and even after the limnic eruption, people were eager to return to it. When the eruption occurred, about 4,000 inhabitants fled the area, and many of these developed respiratory problems, lesions, and paralysis as a result of the gas cloud. Reporters in the area described the scene as “looking like the aftermath of a neutron bomb.”

Survivor Testimony

Joseph  Nkwain from Subum was a survivor of the said occurrence, he described himself when we woke up after the gasses had struck. 

“ I could not speak. I became unconscious. I could not open my mouth because then I smelled something terrible … I heard my daughter snoring in a terrible way, very abnormal … When crossing my daughter’s bed, … I collapsed and fell. I was there till nine o’clock in the morning … until a friend of mine came and knocked at my door … I was surprised to see that my trouser were red, had some stains like honey. I saw some … starchy mess on my body. My arms had some wounds … I opened the door … I wanted to speak, my breath would not come out … My daughter was already dead … I went into my daughter’s bed, thinking that she was still sleeping.

I slept till 4:30 in the afternoon … On Friday ( that same day). I managed to go over to my neighbor’s houses. They were all dead … I decided to leave … most of my family was in Wum … I got my motorcycle … A friend whose father had died left with me (for) Wum … As I rode … through Nyos, I didn’t see any  sign of any living thing … ( when i got to Wum), I was unable to walk, even to talk … my body wad completely weak.”

After the eruption, many survivors were treated at the main hospital in Yaoundé, the county’s capital. It was believed that many of the victims had been poisoned by sulfur-based gasses. Poisoning by these gasses would lead to burning pains in the eyes and nose, coughing and signs of asphyxiation which is similar to being strangled. The survivors’ interviews and pathologic studies indicated that the victims rapidly lost consciousness and that death was caused by asphyxiation. Skin lesions found on the survivors represent pressure sores, and in a dew cases exposure to a heat source, but there is no evidence of chemical burns or flash burns from exposure to hot gasses. 

Studies And Research From Scientists

Starting from 1995, feasibility studies were successfully conducted, and the first permanent degassing tube was installed at Lake Nyos in 2001. Two additional pipes were installed in 2011. In 2019, it was determined that the degassing had reached an essentially steady state and that a single one of the installed pipes would be able to self-sustain the degassing process into the future, indefinitely maintaining the CO2 at a safe level, without any need for external power. 

After the Lake Nyos disaster, scientists investigated other African lakes to see if a similar phenomenon could happen elsewhere. There were two African lakes that had a phenomenon similar to the Lake Nyos disaster. The Lake Kivu in the Democratic Republic of the Congo which was 2,000 times larger than the Lake Nyos, was also found supersaturated, and geologists found evidence that outgassing events around the lake happened about every thousand years. Another was the Lake Monoun which occurred on August 15, 1984, and is also located on the Cameroon Volcanic line. These particular lakes have earned the title “killer lakes”. 

Lake Nyos As A Modern Example Of An Ancient Process

Some scientists view Lake Nyos as a modern example of an ancient process, positing that massive eruptions of gasses such as carbon dioxide and methane and the result of lowering of oxygen levels triggered the mass extinction of animals such as the terrestrial plants during the late Permian period, about 250 million years ago. One camp believed a volcanic eruption released CO2 and blew up the lake. Another camp thought CO2 was gradually leaking into and being stored in the lake. As years passed, scientists resolved the debate about the origin of CO2. After measuring gas at the bottom of Lake Nyos, they found a CO2-rich layer, where levels of the gas were rising over time, suggesting gradual leakage into the bottom of the lake.


The Lake Nyos disaster had people debating how it occurred, nevertheless we cannot disclose the fact that scientists tried their best to solve the issue. Many people lost their families and many survivors experienced trauma and respiratory problems. 

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