On this day in 1963, a landslide in Italy leads to the deaths of more than 2,000 people when it causes a sudden and massive wave of water to overwhelm a dam.
The Diga del Vajont dam was built in the Vaiont Gorge to supply hydroelectric power to Northern Italy. Located 10 miles northeast of Belluno, it rose 875 feet above the Piave River below and was a full 75 feet wide at its base. The construction of the dam created a large reservoir, which held more than 300,000 cubic feet of water. While the dam was solidly constructed, its location was a poor choice.
The Vaiont Gorge was located in a section of the Alps known for instability. In 1963, the area experienced heavy rains—about 90 inches by October 9. At 10:41 p.m., the wet land could no longer hold and a massive landslide came crashing down from Mount Toc, causing a huge pile of dirt and rocks to plunge into the reservoir at about 70 miles per hour. The impact of the debris caused an immense wave of water to rise as high as 300 feet above the level of the dam.
Workers living alongside the dam were killed instantly. The displaced water crashed over the dam and into the Piave River below. It stormed down the river and engulfed the town of Longarone. Within minutes the town had virtually vanished and nearly 2,000 people were dead. The tsunami-like wave then rushed down to San Martino, where it killed hundreds more.
In the aftermath of the disaster, Mario Pancini, the engineer of the dam project, was summoned to court to answer questions regarding what was known of the geology of the area prior to the dam's construction. He killed himself before his scheduled appearance.