Acqua alta (Italian: 'high water') is the term used in Veneto for the exceptional tide peaks that occur periodically in the northern Adriatic Sea. The peaks reach their maximum in the Venetian Lagoon, where they cause partial flooding of Venice and Chioggia; flooding also occurs elsewhere around the northern Adriatic, for instance at Grado and Trieste, but much less often and to a lesser degree. The phenomenon occurs mainly between autumn and spring, when the astronomical tides are reinforced by the prevailing seasonal winds which hamper the usual reflux. The main winds involved are the sirocco, which blows northbound along the Adriatic Sea, and the bora, which has a specific local effect due to the shape and location of the Venetian lagoon.