Forecast Flood Center of Venice italy - acoustic signals warn the population and visitors of Venice 3 hours before a flood reaching 110 cm. Signals start from 18 powerful sirene installed after the enormous flood of 1968. System was perfectioned in december and it's now able to give a more precise information on the height of the flood arriving in the historical center of Venice. Acoustic signals leave from 18 bell towers reporting the following information:

• 110 cm: a long sound on the same note
• 120 cm: two sounds increasing in their note
• 130 cm: three sounds increasing in their note
• 140 cm e oltre: four sounds increasing in their note

Signal is given more times allowing the population and the visitors of Venice an easy understanding of the situation occurring in the next hours.
So it's enough to count the signals provided to understand the height of the flood arriving that day.