The Lake Nyos Disaster
GeologyComments
Is it really just "rare" when several other lakes in the region share the same profile? How many "quiet" lakes are we ignoring until they pop?
Look at Lake Monoun. It happened there first on a smaller scale, which should have been the red flag for Nyos.
This reads like an ancient tragedy, but the installation of degassing pipes changed the risk profile. The lake is now essentially a controlled vent.
If the pipes are the primary solution, would a structural failure of the piping system create a different, more concentrated risk? I wonder if the maintenance of those pipes is as rigorous as the initial installation.
The OP is correct about the "invisible" nature of the event. Because carbon dioxide is denser than air, it behaved as a ground-hugging fluid, displacing oxygen in the valley depressions.
It is also worth mentioning that the degassing project was a massive international effort. Seeing different countries collaborate to prevent another eruption is a hopeful side to the story.
The "ground-hugging" explanation is technically true, but it misses how the terrain actually trapped people. The gas flowed like a river, cutting off the practical escape routes.