Typhoon alley

Kuroshio Current, warm current in the western Pacific Ocean. It flows northeast from the Philippines along the eastern coast of Japan. Near northern Japan, the Kuroshio merges with a cold, southeastern current. The two currents become the North Pacific Current, which runs east through the Pacific Ocean and brings mild temperatures to the west coast of North America. The Kuroshio Current carries tropical waters and heat energy into the temperate latitudes along the east coast of Asia.

The Kuroshio Current is narrow and fast-moving. It is 80 km (50 mi) wide and reaches speeds of 3.5 knots. Like its equivalent in the North Atlantic, the Gulf Stream, the Kuroshio varies in speed and meanders like a giant river, often straying from its normal course. The strength of the current varies with the seasons, reaching its peak between May and August. Its name, which is Japanese for “black stream,” describes its dark appearance in comparison to the surrounding water when viewed from a distance. At closer range, however, the waters of the Kuroshio take on striking blue-green hues. See Ocean and Oceanography.

The Kuroshio Current is sometimes referred to as Typhoon Alley because of the severe tropical storms that follow its warm-water energy path to strike the coasts of the Philippines, China, Japan, and Korea. The Kuroshio region has the world’s highest incidence of severe tropical storms, with most occurring between July and October.