By Scott Longman
Africa’s many cultures are vibrant in their folklore. Some who have lived there say that they believe that some part of that folklore has a grounding in real world events, even if long, long ago. One of the major themes is to use ancient wisdom to keep you alive.
You probably didn’t know that your lake can kill you. That does not mean some fanged beast in the lake, nor simply going buoyancy-negative. No, the Lake itself may decide to come kill you and everyone with you. But the folklore of the Bafmen people already knew that.
The Bafmen had a piece of tribal wisdom that warned of an evil spirit lurking in the depths of their local lake. Indeed, there was a rule: the one thing you do not do is settle down by the lake. Instead, you had to live away from and above it.
Cameroon, where the lake in question is located, has a shifting mix of peoples and customs, and at some point, peoples not sharing of the Bafmen lore came and saw the beautiful shores of an equatorial lake, and settled there…right up until about 9:00 pm on August 21, 1986.
In an explosive instant, a horrific tsunami erupted from the lake’s depths. One lakeside promontory was vertically denuded of vegetation up to a staggering 286 feet. As the wave blasted ashore, it killed and decimated everything. But the tsunami was only the opening bars to the opus magnum that was to follow.
The opus magnum was an odorless, poisonous gas that had caused the tsunami and then escaped into the surrounding air. The gas cascaded across the shores and to the lower end of the lake basin, pouring down the two valleys beyond.
It killed everything but plants. It killed livestock, birds and insects. And it killed people. The gas left a surreal scene out of science fiction: dead everywhere, frozen in place where they were at the instant it hit. And, unlike normal equatorial African experience, there were no flies on the bodies, because the flies were dead, too. In all, it killed nearly 1,800 people.
And to complete those already demonic visuals, the normally inviting blue waters of the lake had turned a morbid blood red. That would later prove to be from the pushing to the surface of iron-rich waters which then rapidly oxidized, but it’s hard to believe that any of the survivors saw it that way.
The Bafmen knew that it was simply the evil spirit of the lake showing up again.
Of all the metaphors to have for a phenomenon that wiped out that enormous number of people, it seems ridiculous to choose a bottle of soda, but that’s actually perfect. The disaster was a massive release of CO2, just like shaking the bottle and ripping off the cap on the soft drink from Hell, and for exactly the same reasons of chemistry and physics.
Lake Nyos had three bad things going for it: its location over volcanic magma, its great depth, and its location on the equator.
The magma produced prodigious quantities of carbon dioxide, which then percolated upward. Where that gas emerged at the deep bottom of the lake, it got all but literally bottled up.
The second problem is the depth of the lake. It is deep enough to swallow a sixty-five story building and not interfere with your waterskiing. That depth means the water down there is under extremely high pressure, so also is the CO2.
The third whammy on Lake Nyos is that it is almost on the equator. That means no seasonal changes. In most of the lakes of the world, seasonal changes cause some deep mixing of waters. Not here.
The overlying waters of Lake Nyos function identically to a bottle cap on all of the heavily CO2-saturated waters at the bottom. Nobody’s figured out just what exactly triggered it, but, once the pressure of that water cap was relieved in some kind of column, even just for an instant, the pressure-monster below roared into it, hell-bent for the surface.
Eventually, international teams figured it out and came up with a pressure release fix that might finally allow that old demon of Bafmen folklore to rest. Us? We’ll choose to still respect the Bafmen, and set up camp with them—on the highground.
SIDEBAR: The Radically Larger Disaster Waiting To HappenThere is the cataclysmically larger problem of a Lake Kivu. That body of water straddles the border of Rwanda and the Democratic Republic of Congo, and it shares the insidious geology at issue here. The Lake Kivu threat dwarfs Nyos, for three reasons. First, the lake is 2,000 times larger than Nyos, and worse, twice as deep. Second, the particular microbial action of that lake turns much of its CO2 into methane. Methane will still asphyxiate you like CO2, but includes the radically increased danger of also being explosive: Imagine a cloud the size of, say, Cincinnati, reaching an ignition source. Third, the city of Buvaku is within the immediate danger zone at Lake Kivu, with onemillion inhabitants. That threat isn’t just hypothetical: Geologists have found evidence of historic, recurring mass extinction events around Lake Kivu. The folklore of the Bafmen was right.
