On August 21, 1986, nearly 1700 people and 3500 livestock were found dead in three villages surround
On August 21, 1986, nearly 1700 people and 3500 livestock were found dead in three villages surrounding Lake Nyos. Other than minor burns on some of the deceased, no one could understand what killed so many in one night, and without warning. Survivor accounts say that a loud explosion was heard, and then it became extremely difficult to breathe. Survivors then say that they passed out, and when they woke up, everyone else was dead. The unfortunate event was in fact caused by the lake itself. Lake Nyos (as well as only two other lakes in the world - Lake Monoun and Lake Kivu) has a large concentration of Carbon Dioxide (due to leaks from magma beneath the surface) laying at the bottom of the lake which can be released during a lake turnover. The night of the Lake Nyos Disaster, about 1.6 million tons of CO2 exploded through to the lake surface, and swiftly drifted towards the surrounding villages as a deadly fog. Many scientists agree that a landslide into Lake Nyos is the likely cause of the turnover and mass release of gas. The villagers died of asphyxiation, and the minor burns on some of the victims were akin to frostbite (caused by the icy CO2 gas that was released - the fog of CO2 was caused by the sublimation effect of dry ice, the solid form of Carbon Dioxide). Scientists and experts suspect that about 1 cubic kilometer of gas was released. To put this number in perspective, the amount of released gas in the lake caused water levels to drop by a meter. The Lake Nyos Disaster is the first large-scale asphyxiation by natural causes. To prevent a repetition, a degassing tube that siphons water from the bottom layers of water to the top allowing the carbon dioxide to leak in safe quantities was installed in 2001, though additional tubes are needed to make the lake safe. -- source link