They Ignored Every Warning: The Vajont Dam Disaster (1963)

On October 9, 1963, a technician at the Vajont Dam warned that the mountain above the reservoir had started to move. Thirty-nine minutes later, a slope of Monte Toc slid into the lake, a wave went over the dam, and the Vajont Dam disaster destroyed the valley below. The dam itself held. This documentary traces five warnings that came before that night: a deadly slide at a neighboring dam, a journalist, a geologist, the mountain itself, and the man in charge of building the dam. We look at the engineering failure behind the disaster: the landslide warning signs that were documented, what the company did about them, why its instruments could not see where the slope would actually slide, and why Italian courts later disagreed about whether the disaster was foreseeable. CHAPTERS 0:00 The Night of October 9 0:59 The Mountain That Walks 2:01 Three Warnings 4:25 The Lever 7:15 Seven Hundred and Ten 8:49 The Night 11:10 Why Nobody Stopped It 12:59 What Remained A note on the figures: casualty numbers for this disaster vary between sources. The video uses the official figure and says so. Statements that rest on accounts rather than documents are marked as such in the narration ("reportedly", "according to"). If you like stories where we take a disaster apart, link by link, subscribe for more real accident investigations. And tell us in the comments which historical failure you want to see covered next. SOURCES & CREDITS Maps, diagrams and schematics are original illustrations made for this channel, not actual footage. The scale gauge is schematic, based on Genevois & Ghirotti (2005), not to scale. The headline of Tina Merlin's article is shown in translation by the channel. Modern photographs of the dam are used for illustration. Photographs (full per-file list with Wikimedia Commons links in the pinned comment). Photos were cropped, scaled and slowly zoomed. Public domain: U.S. Army / SETAF (1963), Sgt. Bobbi-Jo McGinley (U.S. Army, DVIDS), Ispettorato Vigili del Fuoco, Maurizio Reberschak, VENET01 (cabina comandi), and unknown photographers. CC BY-SA 4.0: Thilo Parg, VENET01, Im Fokus, Davide Mauro, Marchetto da Trieste. https://creativecommons.org/licenses/by-sa... CC BY-SA 3.0: Frisia Orientalis, Stefano.aurighi, Tiia Monto, Pigiuri, Jonathan.astolfi, ProfessorX, Lamberto Zannotti, Ziegler175. https://creativecommons.org/licenses/by-sa... CC BY 4.0: Gianmarco139. CC BY 3.0: Davide Cavalli; Willy Pragher / Landesarchiv Baden-Wurttemberg. CC BY 2.5: Christian Thiergan. All via Wikimedia Commons, Europeana and DVIDS. Maps: Natural Earth (public domain). Terrain: Copernicus WorldDEM-30 (c) DLR e.V. 2010-2014 and (c) Airbus Defence and Space GmbH 2014-2018, provided under COPERNICUS by the European Union and ESA; all rights reserved. Rivers and place data: (c) OpenStreetMap contributors, ODbL 1.0, https://www.openstreetmap.org/copyright Typeface: IBM Plex (SIL Open Font License 1.1). Music: Pixabay Content License. Tracks by Universfield, Liecio, Leberch, NumbTheFeelings, The_Mountain. Closing piano: "A sad and painful piano piece" (CapCut music library). This channel tells real accidents and engineering failures in a respectful, source-based way. If you spotted an error, tell us in the comments and we will check it.