What is acqua alta?
Acqua alta, literally high water, is the typically understated way in which Venetians refer to the periodic flooding of the city during periods of so-called spring tides. It’s caused primarily due to the natural geography of the Venetian lagoon. The lagoon closed off from the open sea by a series of long islands with gaps in between. At certain times of the year, higher than usual tides are augmented by winds (known as the bora and scirocco) which blow north up the Adriatic sea, forcing sea water into the mouths of the lagoon and preventing lagoon water from leaving.