Acqua Alta literally means “high water”.
Acqua Alta is a phenomenon that takes place in Venice during autumn and winter, in between October and December, when the northern Adriatic coincide with a warm sirocco from North Africa. When the two coincides, it causes the sea water-level to rise, known as high tide (alta marea). During high tide, large amount of sea water flows into the Venetian lagoon, creating acqua alta phenomenon in Venice.
High tide and low tide cycle alternately every 6 hours. During high tide, acqua alta will normally stay for about 3 to 4 hours.
The high water level (acqua alta) is measured based on the tide level at Punta della Salute, Venice at mareographic zero. At Mareographic zero: +100cm means 5% of the town is covered by water. Increasingly, +110 cm: 14%; +120 cm: 29%; +130 cm: 43%; over +140 cm: 54% of the town is covered by water.
Venice and Venetians are used to dealing with “acqua alta”. When the sea level is forecast at +110 cm on the mareographic zero, the population will be alerted by acoustic signals, or text messages (for those who register to receive free high tide information from the City Tide Centre). Elevated platforms are set along the main streets to allow easy walking passage. Public water-buses keep on operating, although some bus-lines may be subject to changes. Access to majority of the town is open. When an exceptionally high acqua alta occurs, for example +120 cm and above on the mareographic zero, the famous “acqua alta boots” will be needed. The inconvenience normally only lasts for a few hours, until the water level goes down again.
Acqua alta does not stop Venice from operating. Venice and Venetian are so used to coping with it. However, acqua alta can create discomfort and inconvenience to the tourists. In that case, tourists can choose to be patience and wait for a few hours until the water level decreases. But, what is the point of visiting Venice during Acqua Alta season if not for venturing out the unusual lifestyle? For the curious or adventurous tourists, I would suggest you buy a pair of acqua alta boots and visit the town in a quite unusual way. Or, do something silly or crazy that you will not be able to do anywhere else but in Venice. Go ahead, explore and experience the unusual lifestyle or way of living. Keep an open mind, have fun with it. That is the fun of traveling.
Fact source: City of Venice Government Official Website
To learn about the unique activities in Venice during Acqua Alta, click here.