This Lake Conceals Something So Deadly It’s Hard To Believe, But In 1986 It Killed 1,700 People

Tranquil and nestled among luscious green hills, Lake Nyos in Cameroon is one of the most stunningly beautiful places on Earth. Yet it is far from being the sort of hidden paradise you’d find on a Travel Channel documentary. Deep below the surface, this lake hides a deadly secret.

Lake Nyos lies on the side of an inactive volcano, some 200 miles to the northwest of the Cameroonian capital, Yaoundé. It’s what’s known as a crater lake – a deep body of water that sits inside a volcanic crater. And, indeed, it was volcanic activity that led to an appalling tragedy 30 years ago.

On August 21, 1986, something changed in the lake. Far from being its usual aquamarine shade, in fact, the water was now a foreboding shade of red. Scientists now believe this was the result of iron deposits from the bottom of the lake being forced to the surface. One thing seems more certain, though. It was merely the first act of a drama that ended in one of the most tragic natural disasters in living memory.

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Now while it may look like an ancient formation, Lake Nyos has actually only existed for around 400 years. The special type of crater, known as a maar, that it sits in was in fact created during an eruption. Ground water and streaming lava collided and caused a ferocious reaction – with the resulting explosion leaving the 682-foot-deep crater where Lake Nyos now stands.

Yet although this large body of water may be impressively deep, you have to go even deeper underground to find its most important feature. Around 50 miles beneath the lake sits a large puddle of magma. And it’s this molten rock that’s responsible for the horrific events of 1986.

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Because the magma is live, it gives off a variety of gases; these slowly rise through the bedrock into the lake itself and infiltrate its waters. Now normally this isn’t a problem, but any number of potential hazards can cause these gas reserves to turn deadly. And that’s just what happened 30 years ago.

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One of the gases given off by the magma, moreover, is carbon dioxide. This usually remains trapped within the layers of cold water towards the base of the lake, out of harm’s way. But a combination of events can release the gas in one huge outpouring, leading to a disaster of staggering proportions.

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And on the night of August 21, 1986, that’s precisely what happened. In a violent surge, a vast cloud of the potentially deadly gas was released. It’s been estimated that between 100,000 and 300,000 tons of carbon dioxide rose up through the lake. Some, however, have suggested that upwards of 1.5 million tons of the gas burst out of Lake Nyos on that fateful day.

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The carbon dioxide thrust up through the waters of Lake Nyos at around a staggering 62 mph, escaping out of the northern end of the lake into a valley. That valley itself leads to a handful of populated areas – and when the gas got to them, the results were horrifying.

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Over the course of a few hours, in fact, the speeding cloud of volcanic gases overwhelmed the villages of Cha, Nyos and Subum. It was thought to have hit at around 9:00 p.m., as during the following morning the villagers who survived found their friends and relatives exactly as they had been that night. Some had retired to bed; some had been around fires – but the cloud had left them all dead. Furthermore, it was too much to bear for some survivors, who were so overcome by grief that they took their own lives.

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In total, around 1,700 people died in a single night. Before the tragedy, 800 people lived in Nyos; afterwards, just six remained alive. More than 3,500 livestock were killed, too. According to the BBC, a doctor who treated survivors at the time described their symptoms as “like being gassed by a kitchen stove.”

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And even years later, Ephriam Che, a subsistence farmer who lived on a cliff overlooking the lake, remembered the events of that night with terrible clarity. In a 2003 interview with Smithsonian magazine, he recalled a loud rumbling, like a landslide, that he had heard at 9:00 p.m. before noticing an odd, pale-colored vapor rising above the lake. Sickness also rose in Che, and so he went to bed.

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The next day, however, he found local cowherd Halima Suley amid a scene of devastation. She was trying to rouse her father – but to no avail, as both her whole family and the hundreds of cows she looked after were dead. Chillingly, Che also noted that there were no flies buzzing around the bodies that fateful day; they, too, had perished in the gas cloud.

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In spite of the horrors of Lake Nyos, however, scientists are still unsure of the exact circumstances that released the deadly cloud. Some believe there could have been a mini-earthquake; others hold a volcanic eruption at the lake’s base responsible. Yet another theory is that, after a period of heavy rain, a landslide cascaded into the lake. According to this last theory, the landslide disturbed the water with such violence that the normally trapped carbon dioxide was released, beginning the chain of deadly events.

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Indeed, Dr. George Kling, from the Department of Ecology & Evolutionary Biology at the University of Michigan, visited Lake Nyos shortly after the disaster. What’s more, he found signs of a newer landslide that he believed was the trigger. It’s further theorized that the landslide caused a 330-foot plume of water and foam that sent an 82-foot wave crashing against one wall of the lake.

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Fortunately, efforts have since been put in place to ensure that such a tragic incident doesn’t happen again. In 2001 self-powered “degassing” pumps were inserted into the bottom of the lake to allow the carbon dioxide to be gradually released. This means that a build-up like the one that caused so much devastation is unlikely to happen again.

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But unfortunately that may not be the end of the Lake Nyos story. Why? Because the body of water could well be the location for another major natural disaster. Moreover, if anything, this one could be even worse than the events of 1986. And, once again, it’s all down to the volcanic nature of the lake.

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A study in 2005, for example, showed that the natural dam that holds the waters of Lake Nyos in place is being worn away. Water already seeps through some sections of the wall, and because of the volcanic fault the lake sits on, there’s a very real chance that seismic activity could rupture the head wall entirely. The results, if this happened, would be apocalyptic.

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If the dam fails, in fact, then up to 1.8 billion cubic feet of water could be released. The resulting flood would rush downhill, through Cameroon and all the way past the Nigerian border. Estimates suggest that the area the bursting of the dam would affect is home to somewhere near 10,000 people.

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Local folk tales from the region speak of a malevolent spirit that haunts Lake Nyos. It would come out of the water and slaughter anyone who lived near its domain. And if the 1986 tragedy and the future threats that the people of the region face are anything to go by, there’s more than an eerie ring of truth to those legends of the “bad lake.”

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