Bore

Bore, a tidal phenomenon at the estuaries of certain rivers, also called Eagre. When a river expands gradually towards a very wide mouth, and is subject to high tides, the spring flood-tide drives an immense volume of water from the sea into the river; the water accumulates in the estuary more rapidly than it can flow up into the river; and thus there is gradually formed a kind of watery ridge stretching across the estuary, and rushing up towards the river with great violence and much noise. In some cases this ridge or bore is many feet in height. This phenomenon is observable in several British rivers, as the Severn, Trent, Wye, and Solway. The most celebrated bores are those of the Ganges, Brahmaputra, and Indus: in the Hoogly branch of the Ganges, the bore travels 70 miles in four hours, and often appears suddenly as a liquid wall over 7 feet high. That at Hang-choo-foo is very dangerous; and the Bay of Fundy is remarkable for its tidal phenomena. See TIDE.