Vigilance levels

Normal phase (Normalbetrieb)

The situation is normal; there is no threat of flooding.

Vigilance phase (Bereitschaft)

The weather situation indicates a potential risk of flooding. The SPC moves into 'hydrological monitoring' mode.

Depending on the evolution in the weather forecasts, the SPC moves into its vigilance phase or into its phase of constant observation.

An activation message is published on the Internet site at and e-mailed to a predefined circulation list.

Pre-alert phase (Vorwarnung)

Risk of minor flooding, not causing significant damage but requiring specific vigilance if there are any seasonal and/or exposed activities.

If the evolution at one or more limnimetric stations indicates that the threshold for the pre-alert phase will be reached within 24 hours, and depending on developments in the weather forecasts, the SPC goes into the pre-alert phase. An information bulletin (Hochwasserinformation) is posted of the Internet site at

The information bulletin includes:

  • the assessment of the weather situation, with forecasts of precipitations,
  • the assessment of the hydrological situation.

The information bulletin is updated daily, according to how the situation develops.

Alert phase (Alarmbereitschaft)

Risk of major flooding, causing overflowing likely to have a significant impact on people and property.

If the evolution at one or more limnimetric stations indicates that the threshold for an alert has been reached or exceeded, the SPC goes into the alert phase.

A flood bulletin is circulated. It includes the following information:

  • Assessment of the meteorological situation,
  • Assessment of the hydrological situation,
  • Forecasts of precipitations and water levels (estimate),

The bulletins are updated on average twice a day, morning and evening, or several times daily if the evolution of the situation requires it.

The SPC contacts the duty officer at the HCPN so that the Crisis Cell (Cellule de Crise - CC) can be convened if management of the consequences of the flooding is likely to require the assistance and coordination of several agencies and services. If this is the case, the CC is advised and assisted by the SPC.

Receding floodwater / return to normal:

When the measurements at the limnimetric stations and the weather forecasts indicate a return to normal, the SPC decides to end the alert, pre-alert or vigilance phase.

A bulletin is posted once the flood is over. No more bulletins and statements are posted. The data concerning the flood is then analysed so that the necessary conclusions can be drawn.

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