In villages by the lake, fires were suddenly extinguished and aminals dropped dead.
People collapsed in doorways or while attempting to rescue others.
 |
Joseph Nkwain, a father and farmer, survived the Lake Nyos eruption
but he was unable to save his daughter who had been napping |
Fatalities occurred 15-miles away, disproportionally killing villagers who were sitting or laying down on the ground.
Those who survived were able to escape to higher ground on motorcycles.
 |
Cecil B. DeMille's The Ten Commandments,
Charlton Heston as Moses parting the red sea |
An exploding lake that turns red and selectively kills people . . . sound very Biblical, but there is a scientific explanation.
 |
Crater Lake in Oregon, South Rim, 2016 by Achmathur
The lake vents CO2 as water mixes and moves to the top. |
Lakes formed in volcanic craters have high levels of carbon dioxide from vented, underground activities.
Typically the gas escapes slowly from the lake as the water turns over.
 |
| Ariel view of Lake Nyos in the Oku Volcanic Fields of Cameroon |
However, Lake Nyos in Cameroon is an unusual body of water. It was formed recently, 400 years ago, and it has little internal current and motion.
In the bottom of the lake, water pressure created a CO2 solution. Over time, the solution became supersaturated until five gallons of gas was dissolved in every gallon of water. Pressure increased until the lake became a bomb.
 |
Two men on Lake Nyos Cameroon by Bill Evans,
USGS Public domain |
An unknown triggering event occurred that started a chain reaction creating a limnic eruption.
Theories on triggering events range from an earthquake to rain, but once pressure on the deep supersaturated water changed, CO2 started to mix with upper layers of the lake. The pressurized gas rapidly formed a column, suctioning water from the bottom of the lake and erupting into the air.
 |
| Orange water in Lake Nyos, Cameroon 2012 |
.3 cubic miles of CO2 was released in 20 seconds. The lake dropped by a meter and iron-rich water from the bottom of the lake oxidized in the air, turning the lake red.
A 160-foot deadly cloud, traveling at 30 mph, rolled into the valleys and villages. Because CO2 is heavier than air, it clung to the ground and extinguished fires.
 |
Lake Nyos disaster
US Geological Survey, public domain |
People napping by the outer reaches of the cloud suffocated while others who were standing, head above the bulk of the gas, were more likely to survive.
4,000 people were impacted by the disaster. The area was evacuated and most of the survivors experienced lung and skin damage.
 |
A degassing jet attempts to prevent another explosion,
from Nyos Degassing
In an attempt to prevent another buildup, a pipe was placed allowing gas to escape to the surface.
Unfortunately, the levels of CO2 is higher than it was 1986 and a natural dam containing the lake is starting to fail.
|
 |
View of the sky and its reflection on Lake Kivu in Goma,
North Kivu province, DR Congo by Myriam Asmani |
Even more alarming, Lake Kivu in Rwanda and the Democratic Republic of Congo, is 2,000 times larger than Lake Nyos, and is also supersaturated.
There is geological evidence that an eruption has happened every thousand years creating flooding and an extensive cloud of toxic gas.
 |
Dawn on Lake Kivu
Town of Bukavu by Abel Kavanagh |
In this case, both carbon dioxide and methane are present in the bottom of the lake. An attempt is being made to extract methane for energy use, but unless the lake can be successfully vented, an enormous limnic eruption appears inevitable.
#Africa #CO2 #NaturalDisaster #Volcano #Eruption #LakeNyos
