Italy, Venice

High Water in Venice – What Happens When the City Floods

High water (or l’acqua alta in Italian) is the name of a phenomenon, unique to Venice, where a particularly high tide causes the city to partially flood. The water level usually only remains high for several hours, before the tide changes and the water drains away back down to a normal level. This phenomenon occurs fairly often, particularly during the winter, and Venetians are well-accustomed to it. For non-Venetians however, it’s an entirely different story. The majority of us will never have experienced something like this elsewhere! If you’re planning to visit Venice during the winter, there’s a chance you’ll encounter high water during your trip. It’s better to come prepared, which is why I’ve put together this guide. It contains everything you need to know about visiting Venice during high water season.

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High Water in Venice: The Basics

High water (l’acqua alta) is a natural occurrence in Venice. It’s where high tides cause the lower-lying parts of the city to flood. This also affects the surrounding islands in the Venetian lagoon. High water can occur numerous times throughout the autumn and winter seasons, but predominantly in November and December. The Venetian lagoon is tidal (tide changes every 6 hours) meaning high water usually only lasts for several hours. When the tide changes and the sea level drops again, the water drains away through the cracks. Afterwards, for the most part, it can seem as if nothing happened at all!

Occasionally, a combination of bad weather, strong winds and a full moon can cause a particularly high tide. This is usually because winds from the south prevent the previous tide from exiting the lagoon. When the next tide comes in, the tide rises much higher than usual, meaning more of Venice floods. These particularly severe high waters can have devastating effects on residents and their livelihoods. When buildings flood to this extent, anything not raised off the ground will likely be ruined by the dirty water.

To combat these increasingly high water occurrences, the city have constructed the MOSE. MOSE is a network of enormous barriers constructed at all the entry points into the lagoon. When required, the barriers can be raised up in order to block the high tide. This will stop high water from entering the lagoon and flooding the islands. The city plan to activate the MOSE barriers whenever there is particularly high sea level forecasted.

Checking the High Water Forecast

To prepare for your trip to Venice, it’s best to check the high water forecast in the days leading up to your trip. This is particularly important if you’re visiting during the winter. You can find the high water forecast on the website of the city of Venice here. Alternatively, you can download the app called ‘hi!tide Venice’ to keep an eye on the tide level forecasts, both before and during your trip.

The high water is measured in terms of how many cm it rises above the normal sea level. The majority of Venice sits at a level of 100cm or higher. Most of the time high water will only cause the extremely low-lying parts of the city to flood.

Another way to be sure of the high water forecast is from the sirens that sound when the high water is going to be over 110cm. The sirens sound about 3-4 hours before the peak of the tide is due. Their eery sound can be heard from all over the city, to warn residents of the incoming water level. The sirens not only warn that high water is coming, but they also announce what the height of the water will be. After the initial ringing tone, there will be between 1 and 4 ringing tones that follow. The tune of the ringing tones remains the same, but they increase in pitch each time. Here’s what they mean:

  • 1 tone – indicates high water of 110cm or more
  • 2 tones – indicates high water of 120cm or more
  • 3 tones – indicates high water of 130cm or more
  • 4 tones – indicates high water of 140cm or more

What to Pack for High Water

Wellies – If you’re planning to go out and explore Venice during high water, the most important thing you’ll need is your boots! On previous trips to Venice I’ve packed wellies by rolling them up and securing each one with a cable tie. Bringing your own wellies is the cheapest and least wasteful option. However, if you don’t want to do that you can also purchase some once you arrive in Venice. You can find a section of wellies sold in hardware stores such as Ratti. Alternatively, during high water season the street vendors in Venice sell disposable plastic knee-length shoe covers. I personally don’t like these as they break easily and create a lot of waste plastic. However, they definitely work as a last resort option.

Thick socks – If you’re going to be wear wellies, you’ll also need thick socks to wear under them for comfort and warmth. Particularly because walking through high water in wellies will make your feet cold very quickly!

Lots of layers – The best way to dress for the cold in Venice is to wear lots of layers. Wearing layers means you can easily remove one when you go indoors, whether that be for a quick snack break, or to explore the many galleries and museums.

Raincoat – Rain doesn’t always come hand in hand with high water, but it’s better to bring one just to be on the safe side. This will also serve as a good layer against the cold!

Comfortable shoes – An absolute essential when visiting Venice is a comfortable pair of shoes. Venice is a city that requires a great deal of walking. When you’re not wearing wellies, your feet will need a rest and some comfort!

Getting Around the City

High water is a normal and accepted part of life for Venetians. The majority of the time when it occurs, daily life simply goes on without interruption. With the addition of welly boots or waders, people go about their days as normal. Children go to school, adults go to work, bins are still collected and public transport operates as usual.

Usually, the majority of the city remains dry and unaffected by high water. The percentage of the city that experiences flooding depends on the height of the tide. Certain areas of the city that are low-lying experience high water the worst, such as St. Mark’s Square which begins to flood when the tide reaches a level of around 82cm. Sometimes when the water is particularly high, the city close off St. Mark’s Square temporarily for people’s safety.

To aid pedestrians in getting around the city during high water, the city set up temporary elevated walkways on certain routes. Here you can view a map from the website of the city of Venice. It indicates which routes usually remain unaffected by high water, as well as where the raised walkways are placed.

A quick summary of useful high water heights to know before you visit:

  • Piazza San Marco – begins to flood at around 82cm
  • Public transport boats (vaporetto) – changes to some lines may occur when the water level reaches 95cm. View any timetable changes on their website here
  • Rialto Bridge – areas surrounding the bridge begin to flood at around 105cm
  • Elevated walkways – can be used to navigate the city until the water is at a height of around 120cm
  • Train Station (Venezia Santa Lucia) – the square in front of the station begins to flood at around 135cm

Things to Do

Most of the time when high water occurs, the majority of the city remains unaffected. Even if there is high water during your trip, there won’t be any shortage of things to see and do! Venice is a city rich in culture and history, with many fascinating attractions to visit. If you choose to venture out during high water, make sure to visit all the main tourist sights. It’s really quite magnificent to see impressive structures such as the Rialto bridge and St. Mark’s Basilica surrounded by water. Alternatively, you may wish to stay indoors and wait it out until the water drains away back into the canals!

For ideas of things to do on your winter getaway to Venice, you can read the full blog post here: 11 Fun Things to do in Venice in Winter. Or, if you’re looking for even more inspiration for your itinerary, take a look at the full Venice Bucket List!

Respecting locals

An important thing to remember when visiting Venice is to remain respectful to locals who still inhabit the city. Venice is such a unique and strange place, it can be hard to imagine that people still live there, but they do. For Venetians, high water is a normal part of life which they have always had to deal with. However, it’s a nuisance and it’s not particularly welcomed.

Occasionally a very high tide occurs which can cause a lot of damage to people’s homes and businesses. For example, on the 12th November 2019 Venice experienced its worst high water since 1966. The water reached a level of 187cm above sea level. This was much worse than what the forecast for that night had predicted, and it rose very quickly due to extremely strong winds. The floods of that night, as well as the following several days, were devastating for many Venetians, and won’t be forgotten for a long time to come.

If you experience high water during your visit to Venice, by all means admire it. It is an incredible natural phenomenon, after all. However, whilst admiring it, try to remain empathetic to the negative impacts it can have on locals in the city.

I hope this guide to high water in Venice helps you prepare for your upcoming trip. Thanks for reading!

Abbey x