<P> A Pacific hurricane is a mature tropical cyclone that develops within the eastern and central Pacific Ocean to the east of 180 ° W, north of the equator . For tropical cyclone warning purposes, the northern Pacific is divided into three regions: the eastern (North America to 140 ° W), central (140 ° W to 180 °), and western (180 ° to 100 ° E), while the southern Pacific is divided into 2 sections, the Australian region (90E to 160 ° E) and the southern Pacific basin between 160 ° E and 120 ° W. Identical phenomena in the western north Pacific are called typhoons . This separation between the two basins has a practical convenience, however, as tropical cyclones rarely form in the central north Pacific due to high vertical wind shear, and few cross the dateline . </P> <Table> <Tr> <Th> Period </Th> <Th> Seasons </Th> </Tr> <Tr> <Th> Pre-1950s </Th> <Td> Before 1900, 1900--09, 1910--19, 1920--29, 1930--39, 1939, 1940--48, 1949 </Td> </Tr> <Tr> <Th> 1950s </Th> <Td> 1950, 1951, 1952, 1953, 1954, 1955, 1956, 1957, 1958, 1959 </Td> </Tr> <Tr> <Th> 1960s </Th> <Td> 1960, 1961, 1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969 </Td> </Tr> <Tr> <Th> 1970s </Th> <Td> 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979 </Td> </Tr> <Tr> <Th> 1980s </Th> <Td> 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989 </Td> </Tr> <Tr> <Th> 1990s </Th> <Td> 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999 </Td> </Tr> <Tr> <Th> 2000s </Th> <Td> 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 </Td> </Tr> <Tr> <Th> 2010s </Th> <Td> 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018 </Td> </Tr> </Table>

Where do hurricanes form in the pacific ocean