[custom_adv] The Italian city of Venice is seeing its worst flooding in decades, prompting local authorities to submit a request for a state of emergency to the country's central government, after an unusually high tide inundated the city on Tuesday.Tides of 140 centimeters (55 inches) or more are known as "acqua alta" in Italian, and generally take place in winter time, according to Venice's municipality website. The high tide on Tuesday peaked at 187 centimeters (74 inches), according to a statement from Venice's government Wednesday morning. [custom_adv] Italian officials estimate the flood waters have caused hundreds of millions of euros in damage. The water reached 1.87 meters above sea level Tuesday. It is the worst flooding in Venice since 1966, when the city was hit by tides up to 194 centimeters (76 inches), according to government statistics.On Tuesday, the Tide Forecasting and Reporting Center of Civil Protection said that 45% of the city was flooded. [custom_adv] It was the second-highest level ever recorded in Venice and just 7 centimeters lower than the historic flood of 1966. Another wave of very high water followed on Wednesday. "Venice is on its knees," Mayor Luigi Brugnaro says as the lagoon city suffers through some of the worst flooding in its history. The highest tide in 50 years has brought seawater that is threatening monuments and works of art in the historic city. [custom_adv] Water driven by strong winds and storms overwhelmed seawalls and smashed brick docks, shoving boats into streets and leaving parts of landmarks such as St. Mark's Basilica and La Fenice Opera House underwater. Although the crypt at St. Mark's has been flooded, a member of the management board tells Italian news agency ANSA the main concern is that water may have damaged the basilica's support columns. [custom_adv] Water poured through wooden boards that store and hotel owners placed in front of doors to hold back water during flooding. Travelers staying on the ground floor of hotels were forced to move to upper floors overnight. At least one death has been reported: "A 78-year-old man was electrocuted due [to] a short circuit, apparently linked to the flooding" in his home, ANSA reports."These are the effects of climate changes," Brugnaro said via Twitter as he surveyed the damage to Venice on Tuesday night. [custom_adv] Pictures on social media showed a city ferry, water taxis and gondolas — another kind of boat — grounded on walkways. At least 60 boats were damaged in the flooding, civil protection officials said. Flooding in Venice during the northern autumn season is a normal and expected occurrence, but high tide data from recent years shows the fingerprints of rising sea levels.St. Mark’s Square at the city center has gone from flooding four times a year in 1900 to over 60 times annually in recent years. [custom_adv] The mayor of Venice declared a state of emergency as six feet of water swept through the low-lying Italian city, the second highest flood in the city’s history. Ken Caldeira, an atmospheric scientist who works at the Carnegie Institution for Science's Department of Global Ecology, said climate change could easily be a factor in Venice’s floods, but warned of over-attributing things to global warming without proper scientific proof. [custom_adv] The surge in water left homes barricaded and streets flooded as residents and tourists waded through knee-high water. Venice’s Archbishop Francesco Moraglia told reporters that winds were seen whipping up waves on the square and that the famous Basilica of the same name also flooded Tuesday for just the sixth time in twelve centuries - the fifth time was in 2018. [custom_adv] The city’s famous Piazza San Marco was flooded by more than three feet of water, according to Italian news agency ANSA, and the water level could rise to as much as five feet. While flooding is a complex phenomenon with many causes, the effects of climate change on sea-level rise, and the intense rainfall that comes with the greater capacity of a warming atmosphere to hold more moisture, are increasingly recognized as factors that can boost natural variation in weather patterns. [custom_adv] The high waters, known as “acqua alta,” flooded 85 percent of the city, according to city officials. Venice authorities said the water level peaked at 1.87 meters, or just over six feet, second only to a record flood in 1966. [custom_adv] Those factors together, along with the more frequent extreme weather events associated with climate change, contribute to floods. In its nine-century history, the opulent St. Mark’s Basilica has flooded six times — twice in the past two years. [custom_adv] On Wednesday, Venice’s usual throng of tourists had to contend with being inundated by water. Some tried to tiptoe out of their hotels on makeshift planks. Luigi Cavaleri, an engineer at the Institute of Marine Sciences in Venice said the city’s subsidence and the rising sea levels meant that Venice was sinking at a rate of one-fifth of an inch a year. That means that the city will be submerged by water more frequently. [custom_adv] Tables usually used for visitors drinking their Aperol spritzes were instead bobbing in water. Some hotels lost electricity. Mr. Cavaleri said last year’s storm was a much more serious event, but noted, “Floods will continue.”Had the flood system been operational, he said, “the city might have been spared. Hopefully, it will be for the next flood.” [custom_adv] One city hall official, Claudio Madricardo, speaking by telephone, said he was stranded at home and could not leave because the water levels outside were higher than his boots. With more than 85 percent of the city flooded, Brugnaro says the city is in a state of emergency and that he has asked Italy's government for help. [custom_adv] Italian news agency ANSA said two people died on the small barrier island of Pellestrina, including a 78-year-old who was electrocuted while performing repairs on his flooded home.