There are such places on our beautiful planet, approaching which is very dangerous for life. One of these places is Lake Nyos in Cameroon (sometimes the name Nyos is found). It does not flood the surroundings, has no whirlpools or whirlpools, people do not drown in it, no large fish or unknown animals have been met here. What's the matter? Why did this reservoir deserve the title of the most dangerous lake?
Description of Lake Nyos
According to external characteristics, no deadly phenomena are striking. Lake Nyos is relatively young, only about four centuries old. It appeared when the maar, a flat-bottomed volcano crater, was filled with water, at an altitude of 1090 m above sea level. The lake is small, the surface area is slightly less than 1.6 km2, the average size is 1.4x0.9 km. The insignificant size is made up for by the impressive depth of the reservoir - up to 209 m.By the way, on the same mountain volcanic hill, but on its opposite side, there is another dangerous lake Manun, which has a depth of 95 m.
Not so long ago, the water in the lakes was clear, had a beautiful blue tint. The land in the high mountain valleys and on the green hills is very fertile, which attracted people who grow agricultural products and raise livestock.
Volcanic activity is still going on in the rock formation on which both lakes are located. Carbon dioxide, located under the magma plug, looks for a way out, finds cracks in the bottom sediments of lakes, enters the water through them and then dissolves in the atmosphere without causing any tangible harm. This continued until the 80s of the XX century.
Limnological trouble of the lake
Such an incomprehensible word for many, scientists call a phenomenon in which a huge volume of gas is emitted from an open reservoir, which leads to large losses among people and animals. This happens as a result of gas leakage from the deep layers of the earth under the bottom of the lake. In order for a limnological disaster to occur, several circumstances are necessary:
- The inclusion of the "trigger". The impetus for the onset of a dangerous phenomenon can be an underwater volcanic eruption, the ingress of lava into the water, landslides in the lake, earthquakes, strong winds, precipitation and other events.
- The presence of a large volume of carbon dioxide in the mass of water or its sharp release from under the bottom sediments.
We advise you to look at Lake Baikal.
It so happened that on August 21, 1986, the same "trigger" worked. What was the impetus for him is not known for certain. No traces of eruptions, earthquakes or landslides were found, and no evidence of strong winds or rain was found. There is probably a connection with the low amount of precipitation in the area since 1983, which led to a high concentration of gas in the lake water.
Be that as it may, that day, a huge amount of gas burst out through the water column in a high fountain, spread like a cloud over the surroundings. Heavy gas in the spreading aerosol cloud began to settle to the ground and choke all life around. On the territory up to 27 km from the lake that day, more than 1,700 people and all animals said goodbye to their lives. The lake water became muddy and muddy.
After this large-scale event, a less deadly phenomenon at Lake Manun became noticeable, which happened on August 15, 1984 under similar circumstances. Then 37 people lost their lives.
Prevention measures
After these events on Lake Nyos in Cameroon, the authorities realized the need for constant monitoring of the state of water and volcanic activity in the area so that 1986 does not repeat itself. Out of several ways to prevent such phenomena (raising or lowering the water level in the lake, strengthening the banks or bottom sediments, degassing) in the case of lakes Nios and Manun, degassing was chosen. It has been in use since 2001 and 2003, respectively. The evacuated residents are gradually returning to their homes.
