On the 9th of October, 1963, a mega tsunami swept along the Vajont river valley in northern
Italy.
The wave wiped several villages out of existence, causing a level of destruction previously
unseen in peacetime.
In the immediate aftermath it seemed as though there could be only one possible cause: the
Vajont Dam – one of the tallest dams in the world – must surely have collapsed.
But it had not.
In fact, despite the incomparable destruction further down the river valley, the Vajont
Dam stood almost entirely intact.

Background

The idea for the Vajont Dam had first been suggested in the 1920s.
As Italy industrialised, the need for electrical power was growing.
Constructing a hydroelectric dam would be one way to meet that need.
The project, however, faced numerous delays – not least those caused by the advent of
World War II.
Once peace returned to Europe in 1945 the project was picked up once again, and serious
work towards realising it began.
The first step in the process was to survey the chosen site: a narrow, steep-sided section
of the Vajont river valley near the base of Monte Toc.
These surveys were carried out by The Adriatic Electric Company, a government-backed company
responsible for construction of the dam.
Their analysis of the geology of the area determined that it was stable enough for construction
to go ahead.
Work began in 1957… but there were a number of setbacks.
As workers tried to complete new roads leading to and from the dam, they were hampered by
unexpected ground movement.
The slopes of Monte Toc often shifted or slid.
Independent experts were brought in to conduct assessments, and warned that the whole mountainside
was unstable.
This fact that was driven home when a landslide at the nearby Pontesei Dam created a massive
wave that overtopped the dam, swamped a power plant and killed a construction worker in
1959.
The history of landslides in the area was common knowledge to local residents.
Some of them even referred to Monte Toc as “The Mountain That Walks” because of how
often it moved.
The Adriatic Electric Company, however, was reluctant to abandon or scale back the project
– which was, after all, a prestigious piece of civil engineering.
Their own studies contradicted those provided by independent experts, and concluded that
the dam would be safe so long as it was carefully managed.
Journalists who drew any connection between landslides and earth movements in the area
and the safety of the Vajont Dam were, on some occasions, sued by the government, and
soon fell silent.
By the 4th of November, 1960, construction was mostly complete, and the Adriatic Electric
Company had begun filling the reservoir behind the dam.
As the water level rose, a significant landslide took place, with a huge quantity of rock and
soil crashing down into the growing lake.
The resultant wave did not overtop the dam, but was alarming enough to prompt the Adriatic
Electric Company to carry out more research.
The company put its engineers to work constructing models of the dam and the valley to simulate
what might happen in the event of another landslide.
They used the speed and size of the 1960 slide as a starting point, and carried out a barrage
of tests, ultimately concluding that the dam would be safe so long as it was not filled
above a height of 700 metres (or 2297 feet).

The Vajont Dam Disaster

In 1963, after months of rain, another landslide appeared imminent, with trees and rocks crumbling
into the lake.
The mayor of the lakeside village of Erto was so worried that he called for an evacuation.
Engineers at the dam, however, were unconcerned.
In accordance with the research conducted by the Adriatic Electric Company, the water
level in the reservoir had been lowered to the point that they were certain no landslide
could possibly cause a wave that would overtop the dam.
So confident were they in this assessment that some workers gathered on top of the dam
to watch the landslide and ensuing wave.
When it finally came at 10:39pm, those working at the dam were among the first to die.
A tract of land the size of a small town plunged into the lake over the course of just 45 seconds
– much faster than anticipated.
This both raised the water level and created a massive wave that spread out in all directions.
This wave overtopped the dam and swept on down the river valley in a solid wall of water
the height of a 70-storey building.
The waves which spread out across the lake destroyed the village of Erto, which had only
been partially evacuated.
The wave that flowed down the river valley swallowed up farms, houses and numerous settlements
as it went.
The villages of Longarone, Pirago, Rivalta, Villanova and Faè were all wiped off the
map.
The wave swept away trees, rocks, buildings, cars and people, leaving behind nothing but
a flat plain of mud.
As it entered the narrow valley, the wave pushed ahead of it a wall of air that crashed
into anything in its path with the power of a hurricane.
Windows broke, people were bowled off their feet, cars picked up and thrown and houses
flattened.
Following seconds behind this destructive storm was the wave itself: a churning mass
of water and debris that proved deadly to almost anyone caught up in it.
One survivor, Micaela Colletti, a child at the time, related her experience of the disaster:
“I heard what I thought was a thunderclap.
It was incredibly loud.
My granny came into my room and said she was going to close all the shutters because a
storm was coming.
At exactly the same moment all the lights went out and I heard a sound, impossible to
describe properly.
The closest thing I’ve ever heard to it is the sound of metal shop shutters rolling down,
crashing shut, but this was a million, a billion times worse.
I felt my bed collapsing, as if there was a hole opening up beneath me and an irresistible
force dragging me out.
I couldn’t do anything.
I had no idea what was happening.
When they pulled me out there was a popping sound, like when you open a bottle, and someone
said ‘We’ve found another old one’.
I was just 12 but I was covered in mud and completely black and must have looked like
an old woman.”
Micaela was among a lucky few to survive.
In the majority of the flood-hit towns, around 80% of residents were killed within the first
15 minutes of the disaster.
With bodies buried by debris or washed miles downriver, an exact death toll is difficult
to determine, but by most estimates, the flood killed at least 2,000 people.

The Aftermath

Though the Italian army was despatched to attempt a rescue operation, the most they
were able to do in many cases was to recover and lay to rest the bodies of those killed.
In the aftermath of the disaster, the government insisted that the flood had been an unavoidable
natural disaster.
Indeed, it had been caused by months of rain, and a landslide – both conventionally natural
disasters.
The fact that the dam had been situated in such an ill-advised location was barely acknowledged.
Because it was a natural disaster, the government was able to pay a lesser amount of compensation
to many survivors, or outright deny compensation claims in some cases.
The village of Vajont was built to provide housing for many of the survivors, although
some chose to return to the land where their houses had stood before the flood.
The government discouraged but allowed this, and turned its attention to industrialising
the area as much as possible in an attempt to aid its economic recovery.
For some years the Vajont Dam Disaster was regarded as a regrettable accident in the
pursuit of progress, the result of an uncontrollable natural phenomena.
It was only over the course of many years that the role played by the government and
by those working on the dam project was acknowledged.
Now the dam is considered an example of a grave error of judgement – a project pursued
in spite of numerous warning signs.
The dam remains in place.
Though the uppermost portion of the structure was damaged by the wave, it remained largely
intact.
It has since been repaired, but is no longer used to provide hydroelectric power.
Instead it is a tourist attraction and a memorial.
It is still one of the tallest dams in the world… but it holds no water, and instead
serves as a reminder of one of the most destructive and needless disasters in Italian history.