Landslides and avalanches in the mountains are most often the result of one or another natural phenomenon - an earthquake, volcanic eruption, or general warming. But it also happens that their descent can provoke man-made human activity, sometimes even an ordinary echo. For example, during the First World War, when hostilities were taking place in the Tyrolean Alps, powerful snow layers moved because of the roar of artillery shots. Giant avalanches in these places have broken down before, and people, knowing their insidious nature, try not to make noise, and if possible, avoid dangerous places.
But in 1963, not far from the Tyrolean Alps, in the valley of the Piava River, surrounded by rocky shores and made famous by Ernest Hemingway's novel "Farewell to Arms!", A real tragedy broke out. In the upper reaches of this turbulent river, north of Venice, in 1960, the most powerful Vajont Dam was built with a height of 265 meters. The dam was twenty meters wide. In those years, it was considered one of the highest in the world. Numerous crowds of noisy and curious tourists came to see it. The places there are beautiful, but breathtaking from the height. The dam was erected in such a way that it would withstand not only the pressure of water, but also an earthquake, if this happens. Before the construction, detailed geological studies were carried out, as a result of which it was recognized that there was no great danger of landslides. Only loose deposits can be displaced, and their volume is small. It will not exceed half a million cubic meters, and this does not pose any danger to the dam.
In July, when the reservoir was filled with water, the slow displacement of loose material that had begun earlier on the slope of Mount Monte Toc accelerated. On October 1, people noticed that animals were fleeing from the mountainside. A week later, the rate of displacement of loose material increased even more, and on October 9, the entire mountainside slid by thirty centimeters. The residents of the village near the dam were very alarmed, and since it was also raining, their fears became much more serious. However, no special evacuation order was issued.
In the late evening of October 9, a series of sharp blows were heard from the direction of Mount Monte Tok, and the entire slope collapsed. Not half a million cubic meters of stones, but as much as one hundred million cubic meters collapsed into the reservoir at a speed of one hundred kilometers per hour. A stone stream swept over the dam and rushed up the opposite slope to a height of 130 meters.
The rising wave poured over the dam and fell from a height of four hundred meters. First, she flooded and devastated the village of San Martino. The village of Casso under the Monte Burgo mountain was completely destroyed. Houses built above the level where the wave reached were literally blown away. The wave overflowing through the dam reached a height of 165 meters, but it did not damage the dam itself.
Forty million cubic meters of water poured into the Piava river valley. The first on its way was the town of Longarone. All the houses in it were destroyed, and all its inhabitants, every single person, perished during this terrible tragedy.
Inhabitants of other settlements found themselves in a hopeless position. Water destroyed one after another the villages of Rivalto, Pirago and Villanova, and it took her only fifteen minutes. Spilling wide, it left behind ruins and more than two thousand dead people. No one who would have seen this catastrophe with their own eyes remained alive, no one survived it. The bodies of the victims were then found eighty kilometers from the dam.
The reservoir after this disaster turned out to be half filled with loose material, and the Weyont Dam was unusable. Then, of course, some experts in engineering geology agreed that the site for the dam was poorly chosen. However, most continue to argue that this disaster is one of the unpredictable.
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From the book: "HUNDRED GREAT DISASTERS". N. A. Ionina, M. N. Kubeev