Acqua alta in Venice - instructions for use

Acqua alta in Venice is a frequent topic in the media all over the world. But how does it work exactly? Here is some useful information from Venice Municipality site: "The acqua alta, as the seasonal flooding is known, is a natural phenomenon, which has always been a feature of Venetian life.

Usually, tidal events have a very short duration. For example, when the high tide reaches a maximum value of 120 centimetres, it lasts an average of less than an hour and a half.

Even when there is high water, you can still move around the city walking on designated pedestrian routes - partly consisting in temporary elevated platforms - which can be used up to when the height of the tide reaches 120 centimetres.

During high tides, public water transport services work regularly, except in the event of very exceptional tides, although some routes may be modified when the height of the tide reaches 95 centimetres."

Acqua alta is not like an ordinary flooding coming from the sea: as it follows the moon phases, the tide slowly rises up, then it stays up for a few hours (usually 2) at the peak level, then it starts to lower down again. You won't see any waves coming from the sea, just the water slowly rising up from the canals.

How do you get notice of acqua alta? Venice Municipality warns residents using sirens, about 3 hours before the forecasted peak level. 

How do you know how high the water will be? The sirens have a different tone according to the forecasted peak level: one note for a peak up to 110cm; two notes for a peak up to 120cm; 3 notes for a peak up to 130cm; 4 notes for a peak over 140cm.

But what do these levels mean?

Again, from Venice Municipality: "Since the walkable ground of Venice doesn’t unfold on a homogeneous plane, the same tidal event occurs in different points of the city in a variable way, depending on the height of the urban pavement." So, with the same tide, you may find some areas which are not affected, and others where you need wellies to walk around.

Moreover, the tide level is estimated as a quota over a conventional zero, which is not the ground level. This means that a 120cm tide peak is not like having water at 120cm from your feet, but usually at least 70cm less.

The pictures below help you figure out the real level of the tide compared to the declared peak, in different areas in Venice.

The acqua alta season usually goes from November to March, and according to the year there could be just a few events (sometimes none at all) or it could happen more frequently, depending also on the winds and current weather conditions.

If you're planning a stay in Winter in Venice, feel free to contact us and let us help you choosing the best apartment for you! All of our flats are well protected by acqua alta, even the ones on the ground floor, but we'll be more than happy to give you our advice and help you choose. Here you have a few suggestions!