The Lake That Exploded

On the evening of August 21, 1986, the people living around Lake Nyos in northwestern Cameroon went to sleep as usual. By morning, 1,746 of them were dead.

There was no earthquake. No explosion. No fire. No warning of any kind. People simply didn't wake up.

Rescue workers arriving at the scene found something beyond comprehension. Entire villages had been wiped out — every person, every cow, every dog, every insect. Bodies lay exactly where they had fallen: in beds, in doorways, on paths. There were no signs of struggle. No signs of panic. People had died mid-breath.

The livestock were dead too. All 3,500 head of cattle in the surrounding valleys. Birds had fallen from the sky. Even insects on the ground were dead. The only survivors were people who had been on high ground — above the invisible line where the gas cloud had settled.

The killer was the lake itself.

Lake Nyos sits in the crater of an inactive volcano. For decades — possibly centuries — carbon dioxide from volcanic activity beneath the lake had been seeping into the deep water, dissolving under pressure like carbonation in a sealed bottle.

On August 21, something disturbed the lake. A landslide, a change in temperature, perhaps even heavy rainfall. The deep water turned over, and the dissolved CO2 was released in a massive burst — an estimated 1.6 million tonnes of carbon dioxide erupted from the lake in a single catastrophic event.

The cloud extended up to 25 kilometres from the lake. It was odourless, colourless, and silent. The victims never knew it was coming.

This type of event is called a limnic eruption. It had happened once before, at nearby Lake Monoun in 1984, killing 37 people. And the terrifying truth is: Lake Nyos still exists, the volcanic CO2 is still seeping in, and the conditions for another eruption are being actively managed — but not eliminated.