Killing Lake Nyos

Lake Nyos is located in western Cameroon, adjacent to Nigeria, in the elbow region of west Africa. It lies within the Oku Volcanic Field, at the northern boundary of the Cameroon Volcanic Line, a zone of crustal weakness and volcanism that extends to the southwest through the Mt. Cameroon stratovolcano. The Oku Volcanic Field contains numerous basaltic scoria cones and maars. Lake Nyos itself occupies a maar crater which formed from a hydrovolcanic eruption 400 years ago. There are about thirty similar lakes in the region.

At 9:30 p.m. on August 12, 1986, a cloudy mixture of carbon dioxide (CO2) and water droplets rose violently from Lake Nyos, Cameroon. As the lethal mist swept down adjacent valleys, it killed over 1700 people, thousands of cattle, and many more birds and animals. Local villagers attributed the catastrophe to the wrath of a spirit woman of local folklore who inhabits the lakes and rivers. Scientists, on the other hand, were initially puzzled by the root cause, and by the abrupt onset, of this mysterious and tragic event. More