Lake Nyos

We recently posted about video of a “lake monster” in Lake Lagarfljót near Egilsstaðir in Iceland.  Notwithstanding that a local panel voted that the “monster” was real, the video has been generally debunked. In Lake Nyos, in the Northwest Region of Cameroon, there is a real lake monster. The deep volcanic crater lake was normally extremely tranquil, yet on August 21, 1986, the lake boiled in great fountains of tumbling water and roiling foam. The waters turned blood red. By dawn, 1,746 people and 3,500 livestock within 25 kilometres of the lake were dead.  Atlas Obscura explains what happened:

Lake Nyos was formed in a volcanic crater created as recently as 400 years ago.  Crater lakes commonly have high levels of CO2 as they are formed by the volcanic activity happening miles beneath them. Under normal circumstances this gas is released over time as the lake water turns over.

But Lake Nyos was different: an unusually still lake, with little in the way of environmental agitation. Rather than releasing the gas, the lake was acting as a high-pressure storage unit. Its deep waters were becoming ever more loaded with gas until more than five gallons of CO2 were dissolved in every gallon of water. Pressurized to the physical limit, Lake Nyos was a time bomb.

On August 21, 1986, something in the lake went off. It is unknown what the trigger was – landslide, small volcanic eruption, or even something as small as cold rain falling on an edge of the lake. Whatever the cause, the result was catastrophic. In what is known as a Limnic Eruption, the lake literally exploded, sending a fountain of water over 300 feet into the air and creating a small tsunami. But far more deadly than the water was the gas.

Some 1.2 cubic kilometers of CO2 was released in roughly 20 seconds. This massive wave of deadly gas swept over the countryside. Villages near the lake had almost no chance of survival, and in nearby Nyos only six out of 800 survived. (Those who did survive mostly did so by quickly escaping to higher ground on motorcycles.) As the CO2 settled, every flame and fire was immediately extinguished, a sign of the doom descending all around Lake Nyos.

The cloud spread far and wide killing people who were as far as 25 km away from the lake. Nearby villagers who came out of their houses to find out what the sound they had heard was were overtaken by wafting clouds of gas and fell dead at their doorsteps. People taking naps were killed without their relatives even realizing anything had happened, as the gas settled on the ground with enough concentration to kill, but left those standing unaffected.

In all, 1,746 people were killed. The villages of Nyos, Kam, Cha, and Subum were all but wiped out and more than 3,500 livestock animals perished in a matter of minutes. The lake itself turned from a clear blue to a deep red, a change that was caused by iron churned up from the bottom, symbolic of the violence of the natural event.

The lake is now being monitored and a pipe has been installed to help the trapped gas escape. Nevertheless, CO2 levels are now higher than in 1986. For now, the deadly lake monster sleeps.