Exploding killer lakes may sound like the subject of a Stephen King novel but they're actually out there, waiting to strike with a CO2 cloud that suffocates every living creature in its path by sucking the oxygen out of the air.
In 1986 Lake Nyos near the border of Nigeria unleashed a deadly CO2 cloud upon the people who lived in the valley below, killing over 1700 villagers and at least 3000 head of cattle.
But how do these killer lakes create a cloud of pure CO2?:
A hydrovolcanic eruption 400 years earlier created a crater in the lake, where massive amounts of carbon dioxide built up over the centuries. Volcanic rumblings continued miles below the surface, with gas seeping into the groundwater to create “CO2-charged soda springs” that bled into the lake, says Dr. George Kling, a biologist at the University of Michigan.
The problem with CO2 is that it builds up, “like in a soda bottle,” Kling says. No one can see the pressure building as long as the cap — in this case, the weight of the water — stays put and forces the gas to dissolve or be submerged. But when that cap is removed, it explodes like a warm, shaken Coke, with bubbles rising to the surface and a giant burst of CO2 escaping into the atmosphere.
Here's a handy illustrated guide that shows what happened inside Lake Nyos:
Luckily there are only three known "exploding killer lakes" in the world, and with only two eruptions on record it's unlikely these fatal cloud creating lakes will be killing again anytime soon.
But those who live near these lakes can't sleep well at night, because they never know when the lakes will strike again...