A general view shows people walking across the flooded St. Mark's Square, by St. Mark's Basilica on November 15, 2019 in Venice, two days after the city suffered its highest tide in 50 years. Filippo Monteforte | AFP | Getty Images

Venice was inundated by exceptionally high water levels on Friday just days after the lagoon city suffered the worst flood in more than 50 years. The central St. Mark's Square was submerged and closed to tourists, while shops and hotels were once more invaded by rising waters bringing fresh misery to the fragile city. Local authorities said the high tide peaked at 154 cm (5.05 ft), slightly below expectations and significantly lower than the 187 cm level reached on Tuesday — the second highest tide ever recorded in Venice.

But it was still enough to leave 70% of the city under water, fraying the nerves of locals who faced yet another large-scale clean-up operation. "We have been in this emergency for days and we just can't put up with any more," said Venetian resident Nava Naccara. The Italian government declared a state of emergency for Venice on Thursday, allocating 20 million euros ($22 million) to address the immediate damage. Mayor Luigi Brugnaro predicted on Friday the costs would be vastly higher.

Mayor of Venice Luigi Brugnaro, Head of Italy's far-right League (Lega) party, Matteo Salvini and President of Veneto Luca Zaia visit Venice during high tide in St. Mark's Square (Piazza San Marco) on November 15, 2019 in Venice, Italy. A new exceptional high tide of 160 cm was registered today at 11.20 am. Simone Padovani | Awakening | Getty Images

"Venice was destroyed the other day. We are talking about damage totalling a billion euros," Brugnaro said in a video posted on Twitter. "This is a state of emergency, but we are managing it." Sirens wailed across Venice from the early morning hours, warning of the impending high tide, and the crypt beneath St. Mark's Basilica was swiftly inundated. After Friday's high waters, forecasters predicted tides of up to 110-120 cm during the weekend. In normal conditions, tides of 80-90cm are generally seen as high but manageable. The mayor has blamed climate change for the ever-increasing flood waters that the city has had to deal with in recent years, with the mean sea level estimated to be more than 20 cm higher than it was a century ago, and set to raise much further. Groups of volunteers and students arrived in the city centre to help businesses mop up, while schools remained closed, as they have been most of the week.

A flooded St. Mark's square (Piazza San Marco) during a new exceptional high tide on November 15, 2019 in Venice, Italy. A new exceptional high tide of 160 cm was registered today at 11.20 am. Simone Padovani | Awakening | Getty Images