In 1986, Cameroon’s Lake Nyos was the scene of an extraordinary and devastating natural disaster. The lake quite literally exploded, releasing 80 million cubic meters of carbon dioxide in just 20 seconds, which caused the suffocation deaths of 1,746 people and 3,500 livestock. The lake experienced what is known as a limnic eruption. Lake Nyos is not the only body of water in the region to carry properties that lead some to term them “killer lakes,” but scientists are working to ensure that this never happens again.
Lake Nyos is what is known as a ‘crater lake’, one that is formed from the underground activities of nearby volcanoes. Lake Nyos itself was formed over five centuries ago. The subterranean rumblings of magma some 50 miles beneath the lake sends carbon dioxide up through the earth, where it is then held within the lake’s waters. Often this carbon dioxide dissipates slowly, and harmlessly, of its own accord.
In the case of Lake Nyos in 1986, something triggered an extraordinary eruption of this carbon dioxide. As Atlas Obscura reports, in 1986 Lake Nyos had “five gallons of CO2 dissolved in every gallon of water… Pressurized to the physical limit, Lake Nyos was a time bomb.” As for what exactly triggered the explosion, no one is quite sure. It could have been anything from a landslide to a light rain on the lake’s edge.
But explode it did, very suddenly, on August 21, 1986. A tsunami was followed by a huge cloud of gas. Of the 800 residents in Nyos, only six survived. And Nyos, along with the towns of Kam, Cha, and Subum were all wiped out. Within a 15 mile radius of the lake, few people or animals survived. And it wasn’t the first time this phenomenon had been seen; just two years early a similar eruption at nearby Lake Monoun claimed 37 lives.
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In the late 1990s scientists found that levels of carbon dioxide in both Lake Nyos and Monoun were above the levels seen in the 1980s that had caused such devastating explosions, and a plan for degassing the lakes was created. With funding from The Cameroonian Government, The U.S. Office of Foreign Disaster Assistance (part of the U.S. Agency for International Development), and The French Embassy in Cameroon, a simple system was put into place using a six-inch-wide tube stretch 666 feet from the gaseous layer of Lake Nyos to the surface. Through this method, C02 is released as a bubbling fountain, rather than catastrophic explosion. The following year a similar system was installed in Lake Monoun.
Lake Monoun is largely now degassed, and quite stable. Lake Nyos remains hazardous, however, with gas levels in 2008 at around 80 percent of those at the time of the disaster. And in 2013 they stood higher than they did in 1986, with a natural dam on the lake’s edge at risk of failing, creating the risk of a combined flooding and limnic explosion event.
Via Weather Channel
Images via Wikimedia Commons