On the night of August 21, 1986, Lake Nyos in Cameroon released a massive cloud of carbon dioxide that rolled down the surrounding valleys and suffocated people and animals in their sleep. By morning, thousands are dead, in one of the deadliest and strangest natural disasters of the twentieth century.

This episode follows the Lake Nyos disaster from the crater lake’s volcanic geology to the silent nighttime gas release, the medical and scientific investigation that identified a limnic eruption, and the long effort to keep it from happening again through controlled degassing and dam stabilization. It’s a story about a hazard you can’t see, and a lake that can rebuild the same deadly conditions if the monitoring ever fails.

*Our hearts go out to the victims of this tragedy and their families. This podcast does not linger on thos ...