Culled from Smithsonian Magazine, September 2003
ON THE NIGHT OF THE APOCALYPSE, Ephriam Che was in his mud-brick house on a cliff above Nyos, a crater lake in the volcanic highlands of northwest Cameroon. A half-moon lit the water and the hills and valleys beyond. Around 9 p.m., Che, a subsistence farmer with four children, heard a rumbling that sounded like a rockslide. Then a strange white mist rose from the lake. He told his children that it looked as if rain were on the way and went to bed, feeling ill.
Down below, near the lake’s shore, Halima Suley, a cowherd, and her four children had retired for the night. She also heard the rumbling; it sounded, she would recall, like “the shouting of many voices.” Agreat wind roared through her extended family’s small compound of thatched huts, and she promptly passed out—“like a dead person,” she says.
At first light, Che headed downhill. Nyos, normally crystal blue, had turned a dull red. When he reached the lake’s sole outlet, a waterfall cascading down from a low spot in the shore, he found the falls to be, uncharacteristically, dry. At this moment he noticed the silence; even the usual morning chorus of songbirds and insects was absent. So frightened his knees were shaking, he ran farther along the lake. Then he heard shrieking. It was Suley, who, in a frenzy of grief and horror, had torn off her clothing. “Ephriam!” she cried. “Come here! Why are these people lying here? Why won’t they move again?”
Che tried to look away: scattered about lay the bodies of Suley’s children, 31 other members of her family and their 400 cattle. Suley kept trying to shake her lifeless father awake. “On that day there were no flies on the dead,” says Che. The flies were dead too.
He ran on downhill, to the village of Lower Nyos. There, nearly every one of the village’s 1,000 residents was dead, including his parents, siblings, uncles and aunts. “I myself, I was crying, crying, crying,” he says. It was August 21, 1986—the end of the world, or so Che believed at the time.
All told, some 1,800 people perished at Lake Nyos. Many of the victims were found right where they’d normally be around 9 o’clock at night, suggesting they died on the spot. Bodies lay near cooking fires, clustered in doorways and in bed. Some people who had lain unconscious for more than a day finally awoke, saw their family members lying dead and then committed suicide.
Within days scientists from around the world converged on Nyos. At first, they assumed the long-dormant volcano under its crater had erupted, spewing out some kind of deadly fumes. Over months and years, however, the researchers uncovered a monstrous, far more insidious geologic disaster—one thought to exist only in myth. Even worse, they realized, the catastrophe could recur, at Nyos and at least one additional lake nearby.
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Che, an energetic man who never seems to stop smiling, walked with me around Nyos’ rim, telling a story he had learned from his grandfather. Long ago, the story went, a group of villagers decided to cross Lake Nyos. One man parted the waters, much as God parted the Red Sea for the Israelites, but a mosquito bit the man on a testicle; when he swatted the insect, he lost his grip on the waters and every villager was drowned. Che pointed toward the lake with the homemade spear he often carries. “They’re between those two rocks,” he said, referring matter-of-factly to the ghosts of that catastrophe. “You hear them talking sometimes, but you do not see them.”
The story falls under the rubric of what anthropologist Shanklin calls “geomythology”—in this case, an account of an actual disaster that would become more fantastic as it passed down the generations, eventually fading into legend. “Details shift over time, but these stories probably preserve real events,” Shanklin says.
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The Scientific Explanation
Over ensuing weeks and months, scientists would piece together the Nyos story. The crater lake is extraordinarily deep (682 feet) and rests atop a porous, carrot-shaped deposit of volcanic rubble—a subaqueous pile of boulders and ash left from old eruptions. Carbon dioxide may remain from this old activity; or it could be forming now, in magma far below. Wherever it comes from, underwater springs apparently transport the gas upward and into the deep lake-bottom water. There, under pressure from the lake water above, the gas accumulates; pressure keeps the CO2 from coalescing into bubbles, exactly as the cap on a seltzer bottle keeps soda from fizzing.
If the lake were farther north or south, seasonal temperature swings would mix the waters, preventing carbon dioxide buildup. Cold weather causes surface waters to become dense and sink, displacing lower layers upward; in spring, the process reverses. But in equatorial lakes like Nyos and Monoun, the deep layers seldom mix with top layers; indeed, the deepest layers may stagnate for centuries.
But something must have detonated the built-up carbon dioxide that August night 17 years ago. One theory is that boulders crashing into the lake (perhaps the rockslide Ephriam Che heard) set it off; the scientists at Nyos noted that an adjacent cliff face bore signs of a fresh rockslide. Or a fluky drop in air temperature, causing surface water to cool and abruptly sink, might have been the trigger, or a strong wind that set off a wave and mixed the layers. Whatever the cause, water saturated with carbon dioxide was displaced upward from the depths; as it rose and pressure lessened, dissolved carbon dioxide bubbled out of solution, and the bubbles drew more gasladen water in their wake, and so on, until the lake exploded like a huge shaken seltzer bottle. (The explosion, they determined, had also brought up iron-rich water, which oxidized at the surface and turned the lake red.)
In addition, the scientists observed that a lakeside promontory had been stripped of vegetation to a height of 262 feet, presumably by a carbon dioxide-driven waterspout rocketing into the air. The explosion released a cloud of carbon dioxide—perhaps as much as a billion cubic yards, scientists estimate—that thundered over the lake’s rim, hit Suley’s family first and poured downhill at 45 miles per hour through two valleys and into the villages of Lower Nyos, Cha, Fang, Subum and, finally, Mashi, which is 14 miles from the lake.
Those on high ground survived. Afew individuals at lower elevations, like Suley, were spared for no apparent reason. The only other survivor in her family was her husband, Abdoul Ahmadou. He had been away on business in Wum that night. When he returned, it was to join his wife in burying their dead, then to flee to a refugee camp near Wum. Amid fears that the lake could erupt again, the military ordered out most of the region’s survivors, around 4,000 in all.
Surving Against All Odds
Survivors have overcome great challenges. On the day of the Nyos disaster, Mercy Bih was on her way to Wum, carrying about $100—a considerable sum in Cameroon—to buy supplies for her 26-member extended family. All her relatives were killed. She was 12. She returned the groceries and was reimbursed the $100, which she saved. Now 29 and the mother of two, she’s the proprietor of the Lake Nyos Survival Good Faith Club, a four-table restaurant in Wum serving cold beer and the best grilled mackerel for miles. “I was lucky,” she says. “Some people got left with nothing.”
Though the Cameroon military had driven out most of those who had not fled the area on their own, Che, living on high ground, was allowed to remain, along with his wife and children, who had also survived. However, his uncle’s seven children had been orphaned by the disaster, and tradition required Che to adopt them all, bringing his brood to 11. Che’s income has been boosted by the foreign scientists working in the area, who pay him to measure lake levels and guard equipment, among other things.
As for Halima Suley, she and her husband now have five youngsters born to them since the tragedy. Just before dawn one morning, we hiked up to Suley and Ahmadou’s new compound, located in a narrow pass above the lake. As a cooling breeze sprang up, we glimpsed thatched huts and cattle fencing coming into view. Out back, Ahmadou milked the cows; the herd numbers only 40 now. Suley greeted us in the family’s perfectly swept yard with her children—from 15-year-old Ahmadou to 2-year-old Nafih. Suley made sweet tea with fresh milk and cradled the little one. “I’m no more thinking about the disaster,” she says. “I have more children. I’m thinking about the children I have now.” She smiled. “The only problem is a lack of cattle to feed them and to pay for them to go to school.”
Ahmadou says, “If I think about what I was, what the family was, I can go crazy. So I try not to. We are believers. Your children can survive you, or you can survive your children—it is all in the hands of God.” He says he appreciates the scientists’ work. “When we feel their presence, we are much more peaceful, because we think something is being done.” But, he admits, “When they leave, we live in fear.”
Click here to read this award-winning article about the Lake Nyos Disaster.
Kevin Krajick's article, "Defusing Africa's Killer Lakes", first appeared in the September 2003 issue Smithsonian Magazine, and was subsequently honored by receiving the Walter Sullivan Award for Excellence in Science Journalism. His articles have appeared in National Geographic, Newsweek, The New York Times, Science, Discover, Audubon, Natural History, Smithsonian and many other publications. Krajick also authored "Barren Lands: An Epic Search for Diamonds in the North American Arctic".
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