A local man from Pellestrina, one of the many islands in the Venetian lagoon, died when he was struck by lightning while using an electric water pump, the fire brigade said.

City officials said the tide peaked at 187 cm at 10:50 p.m. local time on Tuesday, just short of the record 194 cm set in 1966.

Night-time footage showed a torrent of water whipped up by high winds raging through the city center while Luca Zaia, governor of the Veneto region, described a scene of "apocalyptic devastation".

Mayor Luigi Brugnaro said the situation was dramatic. "We ask the government to help us. The cost will be high. This is the result of climate change," he said on Twitter.

He said he would declare a disaster zone and ask the government to call a state of emergency, which would allow funds to be freed to address the damage.

Saint Mark's Square was submerged by more than one meter of water, while the adjacent Saint Mark's Basilica was flooded for the sixth time in 1,200 years - but the fourth in the last 20.

A flood barrier was designed in 1984 to protect Venice from the kind of high tides that hit the city on Tuesday, but the multi-billion euro project, known as Mose, has been plagued by corruption scandals and is still not operative.

Brugnaro said the basilica had suffered "grave damage", but no details were available on the state of its mainly Byzantine interior, famous for its rich mosaics.

Its administrator said the basilica had aged 20 years in a single day when it was flooded last year.

On Its Knees

Some tourists appeared to enjoy the drama, with one man filmed swimming across Saint Mark's Square wearing only shorts on Tuesday evening.

"Venice is on its knees.. the art, the basilica, the shops and the homes, a disaster.. The city is bracing itself for the next high tide," Zaia said on TV.

The luxury Hotel Gritti, a landmark of Venice which looks onto the Lagoon, was also flooded.

On Wednesday morning the tide level fell to 145 cm but was expected to rise back to 160 cm during the day.

Local authorities and the government's civil protection unit will hold a news conference at 1100 GMT.

The overnight surge triggered several fires, including one at the International Gallery of Modern Art Ca' Pesaro, with hundreds of calls to the fire brigade.

Video on social media showed deep water flowing like a river along one of Venice's main thoroughfares. Other footage showed large waves hammering boats moored alongside the Doge's Palace and surging over the stone sidewalks.

"A high tide of 187 cm is going to leave an indelible wound," Brugnaro said.

Much of Italy has been pummelled by torrential rains in recent days, with widespread flooding, especially in the southern heel and toe of the country.

In Matera, this year's European Capital of Culture, rainwater cascaded through the streets and inundated the city's famous cave-dwelling district.

Further bad weather is forecast for the coming days.

REUTERS