History & Politics
The Vajont Dam Disaster Caused a 260 Billion Gallon Wave
Micaela Colletti was 12-years-old, getting ready for bed. First, she heard the squawk of birds, as if they were migrating. Then, there was the sound of a thunderclap. Her grandmother came in to close the shutters saying that a storm was coming.¹
Then she heard what she describes as millions of metal gates grating on each other.
Moments later, the floor was yanked out from under her. Her entire town around her was liquid chaos. She was carried 350 meters away. All before being buried under mud. A day later, she was found, still alive. She is one of the few lucky survivors.
The disaster that wiped out her entire area is one of the worst man-made disasters in history. It happened in Vajont, Italy, and is a very unusual catastrophe.
The greed and thirst for cash
Italy’s Vajont dam was built in the 1950s and was the largest dam in the world at the time. It was built in the Alpine Valley. Today, the dam remains fully intact, unbroken. Yet you won’t see any water on either side of it.
It was the product of foreign aid in the wake of World War II, part of a global effort to rebuild Europe. The goal was to produce hydroelectric power for cities in the region. Government officials were too eager to put this money to use and disregarded warnings from engineers.
Namely, this region of mountains was prone to landslides. This dam’s water ran the risk of softening the dirt beneath the mountains, destabilizing the surrounding earth. Officials countered by insisting the dam be strong and prepared for any amount of force. The problem? Even an invincible dam wasn’t enough for what came next.
The warning shot in 1963
Outside of expert opinions, there were several signs this disaster could happen. When workers built roads leading to the dam, several reported seeing rips and fissures in the ground. Even newly built roads were cracking and splitting. They reported this to regional officials, who then brushed it aside as natural and insignificant.
Then, there was a landslide in 1961:
It caused a rapid water surge. Fortunately, the wave that breached the dam was only seven feet higher than the dam itself. There were no injuries.
The dam is 262 meters tall. Engineers lowered the water level down to 185m to give it more clearance.
The problem? This resulted in lower energy output. So within 18 months, and after political pressure, they started elevating the water levels again. Eventually, the water level was 25 meters lower than the dam itself. Officials estimated this level would accommodate any further landslides.
It’s important to pause here and take a step back. Behind this rundown of actual events, there are human beings living in the towns below. They are going about their daily lives, working, spending time with their families. They are trusting the government to ensure their safety.
And that trust was abused.
The ultimate disaster struck
The summer of 1963 saw exceptional amounts of rainfall. The engineers continued to monitor the mountain and maintain the 25m clearance of the dam.
Their teams failed analysis would arrive in apocalyptic fashion. On October 9th, a faultline on one of the mountains became wet. Its clay lubricated an inner plane of the mountain and destabilized it.
That night just after 10 PM, 260 million cubic meters of earth, rocks, trees, and dirt came hurdling towards the water. For reference, the reservoir itself only contained 115 million cubic meters of water. So you can think of this like a glass of water, that’s almost full, and you drop a huge cylindrical cube of rock into it.
Making it worse, the landslide originated near the peak of a mountain. This caused the rocks to hit the water at more than 70 mph, far faster than geologists anticipated.
The surge caused a wave that rose a full 330 ft higher than the top of the dam. The spillover totaled 260 billion gallons of water. That is equivalent to 39,000 Olympic long course swimming pools.
Longarone is in a thin valley. This caused the water to compress and push through it like a bullet in a chamber. Even worse, this pushed an immensely powerful shockwave of air in front of it. This gust blew the roofs off of most buildings. Later, a majority of the victims and survivors were found with their clothes completely blown off of their bodies.
The wave was of biblical proportions. It demolished all four towns in the valley. A mere 5% of its inhabitants survived. The devastation afterward looked very much like a nuclear blast:
The aftermath and takeaway
This was one of the largest man-made environmental disasters in history. Thousands of people died. Today, most people still don’t know about the event. Today, the dam itself still stands, a memorial both to the victims, and a highlight of extreme failure of the government.
Politicians, who were eager to monetize the dam, continued to disregard safety advisories. They refused to do an adequate study of the soil surrounding the dam. Worst of all, they didn’t advise locals of the full danger they were in.
In the politically polarized aftermath, pro-government conservative newspapers argued that the dam was just a natural disaster, God’s will, and was bound to happen at some point anyway. There were minimal arrests and jail sentences. The entire event, before, during, and after, proved ugly.
Nature doesn’t care about our political squabbles. It doesn’t care who is to blame or who should have done what. Nature does as nature intends to do, with or without us, and without regard for safety.
Today, the Vajont Dam disaster is a staple of civil engineering textbooks. Behind every man-made disaster, you can find a string of failures in the process, a disregard for safety, stacking up to one cataclysmic event. And this is why we must continue to hold those in power, fully accountable for their actions. To do anything less gives them permission to continue the abuse.