Lake Nyos Disaster

The Lake Nyos disaster occurred on August 21st, 1986, at 9:30 PM. This particular lake is more than deep enough to hold a great amount of CO2 – a crater lake on the flank of an extinct stratovolcano, it is 208 meters (682 feet) deep. No one knows the exact cause of the CO2 expulsion, but the main theories are disturbance from the bottom (unusual heat or small explosion from magma, rockslide, etc.) or disturbance from the top (lake overturn). Over 1.6 million tons of CO2 rose from the lake bottom. Since CO2 is heavier than air, it spilled over the northern edge of the crater and flowed downhill the same way that a river might. As the cloud headed towards the three villages of Nyos, Cha, and Subum, it picked up more speed, eventually going 100 kph (62 mph).