Didn't take a lot of reading to discover a few things.
This is the second highest tide we know about in the area. The first was back in the 70s. You know? Back when we were worried about global cooling.
The high point of this second highest tide may have been 6 foot but:
$1:
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.
Venice is in the centre of about 100 little islands connected by canals in a bay. It's subject to flooding.
$1:
In its nine-century history, the opulent St. Mark’s Basilica has flooded six times — twice in the past two years.
The flooding this time was accompanied by high winds and torrential downpours.
What I learned in high school science is tides are affected by the moon.