Qualla: Lake Monoun

Lake Monoun: Introduction

Tue, 24 Mar 2026 00:00:00 GMT

Photo credit SarahTz from Richmond, United Kingdom, CC BY 2.0. On August 15, 1984, residents near a small lake in Cameroon's West Province heard a loud noise around half past ten at night. By dawn, 37 people in the low-lying area nearby were dead. Their bodies showed strange skin discoloration. Survivors described a whitish, smoke-like cloud that smelled bitter and acidic drifting through the darkness. At first, investigators suspected terrorism. The real explanation was stranger and more terrifying: the lake itself had exhaled a massive cloud of carbon dioxide, and the invisible gas had pooled in the valley, suffocating everyone in its path.

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Image: SarahTz from Richmond, United Kingdom | CC BY 2.0

Lake Monoun: A Lake That Breathes Poison

Tue, 24 Mar 2026 00:00:00 GMT

Photo credit Eric Gaba (Sting - fr:Sting), CC BY-SA 3.0. Lake Monoun is a maar -- a crater lake formed by a volcanic explosion -- sitting within the Oku Volcanic Field of western Cameroon. Beneath its surface, carbon dioxide seeps upward from magmatic sources and dissolves into the deep, cold, pressurized water. Under normal conditions...

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Image: Eric Gaba (Sting - fr:Sting) | CC BY-SA 3.0

Lake Monoun: The Night the Valley Fell Silent

Tue, 24 Mar 2026 00:00:00 GMT

Photo credit Buaidh, CC BY-SA 4.0. Carbon dioxide is heavier than air. When it erupts from a lake in massive quantities, it flows downhill like an invisible flood, displacing oxygen and settling into depressions and valleys. The 37 people who died near Lake Monoun were in a low-lying area where the gas concentrate...

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Image: Buaidh | CC BY-SA 4.0

Lake Monoun: Draining a Time Bomb

Tue, 24 Mar 2026 00:00:00 GMT

Photo credit Prosper Mekem, CC BY-SA 4.0. Once scientists understood the mechanism, the question became urgent: how do you defuse a lake? In 1992, engineers began preliminary tests at Monoun using a gas-lift technique borrowed from the petroleum industry. The concept is elegantly simple. A pipe extends from the lake's su...

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Image: Prosper Mekem | CC BY-SA 4.0

Lake Monoun: An Ongoing Vigil

Tue, 24 Mar 2026 00:00:00 GMT

Photo credit Prosper Mekem, CC BY-SA 4.0. In February 2003, a permanent venting pipe was inserted into Lake Monoun, producing an eight-meter fountain as gas-laden water from 73 meters below surged to the surface. The initial success, however, revealed new complications. The deep water is rich in iron, which oxidizes into...

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Image: Prosper Mekem | CC BY-SA 4.0