Dam accident

In the event of an accident involving structures that retain or store water, overflow, spillover or failure of the installation may result in an uncontrolled, sudden increase in drained water and thus to a tidal wave below the dam. The public is warned of Imminent flood waves coming from a dam by the water alert signal or (for water retaining structures without water alarm) by the general alert signal. Warning time may be very short. The likelihood of such accidents, however, is considered to be very low.

If the water alert or general alert is sounded, you have only minutes to leave the area. The flood will damage or destroy buildings and infrastructure below the dam. Like during any other flood, cellars and possibly even raised floors will be flooded. Entire neighbourhoods, roads and railway lines will be scattered with rubble, trees, debris and mud. Roads, communications and electric power supply will probably be disrupted in the affected areas. The affected area will be cordoned off. You might be unable to return to your home for days or even weeks. If the damaged area is extensive and badly accessible for rescue units and relief organisations, you may be on your own or will need to depend on your neighbours for the first hours or even days.

• Vajont (Italy), 1963
• Malpasset (France), 1959

1. Leave the threatened area immediately and move to higher ground.
2. Follow local notices and instructions.

1. Inform yourself via radio and television and follow the instructions given by the authorities and emergency organisations.
2. Call the emergency services only in an emergency.
3. Use the telephone and other important means of communication only for important and urgent requirements (danger of network overload).
4. Use cars and other means of transport only for important and urgent requirements (danger of traffic overload).
5. Act particularly careful in traffic (danger due to breakdown of traffic lights, barriers etc.).
6. Inform and support neighbours and people needing assistance in your vicinity.

• Swiss Federal Office of Energy (SFOE)