Marion Island, one of the two Prince Edward Islands in the southern Indian Ocean, about 1,190 miles (1,920 km) southeast of Cape Town. In 1947 South Africa proclaimed sovereignty of the islands and established a meteorological station on Marion Island in 1948. The islands are otherwise uninhabited. A sub-Antarctic island of volcanic origin, Marion is 115 square miles (298 square km) in area and has a low, domelike shape rising to President Swart Peak (3,890 feet [1,186 metres]). The coastline, exposed and rugged, has steep cliffs rising 500 feet (150 metres) high. The climate is cool (mean annual temperature, 40 °F [4.4 °C]) and stormy, with prevailing westerly winds that bring heavy rain (100 inches [2,500 mm] annually) and snow; cloudless days are rather exceptional. Plants include the Kerguelen cabbage, mosses, and ferns. Birdlife is extensive. Prince Edward Island lies 12 miles (19 km) to the northeast.