Acqua alta Info
- This is the exceptionally high tide which the Venetian lagoon is sometimes subject to during the winter months. It is caused by particular wind conditions but exacerbated by man's impact on the environment. When the water level in the lagoon rises by about a metre or more, up to an extreme of more than 1.40 m, ever-increasing areas of Venice's streets and squares are covered by several centimetres of water. The high water is usually heralded by the sounding of sirens three or four hours before the tide reaches its highest point, and duckboards are put out in the busiest areas to enable pedestrians to get through.