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.
Venice Mayor Luigi Brugnaro attributed the flooding to climate change and called for a state of emergency.
Venice has always lived with a degree of risk, given its location in a shallow lagoon. But it is increasingly imperiled.
The sea level has been rising even more rapidly in Venice than in other parts of the world. At the same time, the city is sinking, the result of tectonic plates shifting below the Italian coast.
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.
“The [increased flooding] is a trend that jibes with the extremization of climate,” said Paolo Canestrelli, founder and former head of the municipality’s Tide Monitoring and Forecast Centre. “If we look at the course of history, we have documents dating back to 1872, and we can see that these phenomena didn’t used to exist.”
Climate scientists predict Venice will be entirely underwater by the end of this century.
The direct cause of this week’s flooding was the combination of high astronomical tides and a strong storm system in the Adriatic Sea. A storm surge from the low-pressure system swirling in the Adriatic helped raise water levels in Venice.
Forecasts indicated that the water level would remain well above normal in the coming days, while ebbing and rising based on the tide.
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. Tables usually used for visitors drinking their Aperol spritzes were instead bobbing in water. Some hotels lost electricity.
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.
“For months now, I have been thinking I should sell my home and leave, because the assets I’d leave to my son one day won’t be worth much of anything,” Madricardo said. “Nobody will want a house in Venice, because the situation will be a disaster.”
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. The news agency said the other death could have been related to natural causes.
Venice has been trying to mitigate flooding with a technological solution: the installation of a massive underwater floodgate system. The project, known as MOSE, is designed to temporarily isolate the lagoon from the Adriatic Sea during times of “acqua alta” — with the use of gates that rise from the water and seal off inlets.
But corruption scandals have paralyzed the project, and construction has been plagued by delays.
Brugnaro, the mayor, indicated in an afternoon news conference that the city’s future was at stake in how it responded to the flooding crisis.
“Venice is an emblem for the whole country,” he said. “We are no longer talking about a local problem, but a worldwide one.
“There were people who were crying today because they’ve lost everything, and we’re not talking about the poor. The point is that there is no longer certainty. You no longer know how to live, and if we want to repopulate, we want to give certainty. It’s the life of the city itself, the future of the city.”
Of course, what attracts tourists is the treasure trove of churches, medieval architecture and artwork by the likes of Tintoretto and Titian. A study released last year in Nature, looking at the vulnerability of UNESCO heritage sites along the Mediterranean, called Venice one of the spots most endangered by coastal flooding.
Standing in St. Mark’s Square on Wednesday, Paolo Chiaruttini, a member of the basilica’s board, said the piazza looked like a “lake.”
“I can only see water, dirty water,” he said.
Chiaruttini said the basilica’s marble suffered water damage even before this flooding and that restoration is painstaking because the church has 110 kinds of marble. He said tourism money from a museum and nearby steeple — “millions every year” — is fed back into repairs and maintenance.
The maintenance of such history, he said, is a “scary job, and it has to be done in normal conditions — not underwater. This [flooding] a disaster for us. It’s a defeat.”
Andrew Freedman in Washington contributed to this report.