Category 5 hurricanes are tropical cyclones that reach Category 5 intensity on the Saffir–Simpson hurricane scale. They are by definition the strongest hurricanes that can form on planet Earth. Hurricanes of this intensity are infrequent in the northeastern Pacific Ocean; only 21 have formed since 1959, and they generally develop in clusters during the same year. Landfalls by such storms are rare due to the generally westward path of tropical cyclones in the Northern Hemisphere. The term "hurricane" is used for tropical cyclones in the Pacific Ocean, north of the equator and east of the International Date Line. A Category 5 Pacific hurricane is therefore a tropical cyclone in the north Pacific Ocean that reached Category 5 intensity east of the International Date Line. Identical phenomena in the north Pacific Ocean west of the dateline are called "typhoons" or "super typhoons". Category 5 super typhoons generally happen several times per season, so cyclones of that intensity are not exceptional for that region. This difference in terminology therefore excludes storms such as Typhoon Paka and Typhoon Oliwa of 1997, and Typhoon Genevieve of 2014, which formed east of the dateline but did not reach Category 5 intensity until after crossing the dateline.