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. They are rare in the eastern Pacific Ocean and generally form only once every several years. In general, Category 5s form in clusters in single years. Landfalls by such storms are rare due to the generally westerly path of tropical cyclones in the northern hemisphere.
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, and simply cyclone. A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean; in the south Pacific or Indian Ocean, comparable storms are referred to simply as "tropical cyclones" or "severe cyclonic storms".
The Pacific Ocean is the largest and deepest of Earth's oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean in the south and is bounded by Asia and Australia in the west and the Americas in the east.
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 dateline. 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 Super Typhoon Paka and Super 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.
An equator of a rotating spheroid is its zeroth circle of latitude (parallel). It is the imaginary line on the spheroid, equidistant from its poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane perpendicular to its axis of rotation and midway between its geographical poles.
Typhoon Paka, known in the Philippines as Typhoon Rubing, was the last tropical cyclone of the 1997 Pacific hurricane and typhoon season, and was among the strongest Pacific typhoons in the month of December. Paka, which is the Hawaiian name for Pat, developed on November 28 from a trough well to the southwest of Hawaii. The storm tracked generally westward for much of its duration, and on December 7 it crossed into the western Pacific Ocean. Much of its track was characterized by fluctuations in intensity, and on December 10 the cyclone attained typhoon status as it crossed the Marshall Islands. On December 16, Paka struck Guam and Rota with winds of 230 km/h (145 mph), and it strengthened further to reach peak winds on December 18 over open waters as the final super typhoon of the year. Subsequently, it underwent a steady weakening trend, and on December 23 Paka dissipated.
The 1997 Pacific typhoon season was a record-breaking season featuring 11 tropical cyclones reaching super typhoon intensity, tying the record with 1965 with the most violent tropical cyclones globally. It has no official bounds; it ran year-round in 1997, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean.
A Category 5 hurricane is defined as having sustained windspeeds of at least 137 knots (157 mph; 252 km/h; 70 m/s) over a one-minute period 10 metres (32 ft 10 in) above the ground. As a tropical cyclone is moving, its wind field is asymmetric. In the northern hemisphere, the strongest winds are on the right side of the storm (relative to the direction of motion). The highest winds given in advisories are those from the right side.
Since the 1959 season, only 18 hurricanes are known to have reached Category 5 intensity. There are no known Category 5 storms occurring before 1959. It is possible that some earlier storms reached Category 5 over open waters, but they were never recognized because they never affected land and remained at sea.
This lists all of the Category 5 hurricanes in the order in which they formed. Only 1994's Hurricane Emilia and 2006's Hurricane Ioke have reached Category 5 intensity more than once; that is, by weakening into a Category 4 or weaker storm and later re-strengthening to a Category 5 storm.
Before the advent of reliable geostationary satellite coverage in 1966, the number of eastern Pacific tropical cyclones was significantly underestimated. 5 hurricanes other than those listed, but they were not reported and therefore not recognized. However, the lack of Pacific Category 5 hurricanes during the late 1970s, 1980s, and early 1990s, is certain.It is therefore very possible that there are additional Category
The weather satellite is a type of satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be polar orbiting, covering the entire Earth asynchronously, or geostationary, hovering over the same spot on the equator.
The minimum central pressure of these storms is, for the most part, estimated from satellite imagery using the Dvorak technique. In the case of Kenna,Ava, Patricia, and Lane, the central pressure was measured by hurricane hunter aircraft flying into the storm. Because of the estimation of central pressures, it is possible that other storms more intense than these have formed.
Atmospheric pressure, sometimes also called barometric pressure, is the pressure within the atmosphere of Earth. The standard atmosphere is a unit of pressure defined as 1013.25 mbar (101325 Pa), equivalent to 760 mm Hg (torr), 29.9212 inches Hg, or 14.696 psi. The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth, that is, the Earth's atmospheric pressure at sea level is approximately 1 atm.
The Dvorak technique is a widely used system to estimate tropical cyclone intensity based solely on visible and infrared satellite images. Within the Dvorak satellite strength estimate for tropical cyclones, there are several visual patterns that a cyclone may take on which define the upper and lower bounds on its intensity. The primary patterns used are curved band pattern (T1.0-T4.5), shear pattern (T1.5–T3.5), central dense overcast (CDO) pattern (T2.5–T5.0), central cold cover (CCC) pattern, banding eye pattern (T4.0–T4.5), and eye pattern (T4.5–T8.0).
The reason for estimating the pressure (in lieu of direct measurements) is the fact that most of these storms did not threaten land.As Kenna, Patricia and Lane were threatening land, their pressures were measured by Hurricane Hunters using dropsondes. While Hurricane Ava never threatened land, it too was flown into by Hurricane Hunters to test equipment and conduct research.
Older storms have incomplete pressure readings, since there were no satellite-based estimates; the only observations were taken by ships, land-based observations, or reconnaissance aircraft when available. Ava's minimum known pressure was measured when it was a Category 4 hurricane, for example. John and Gilma have incomplete pressures because the Central Pacific Hurricane Center, in general, did not publish pressure on systems in the central Pacific (140°W to the dateline) at the time. This list is not identical to the list of most intense Pacific hurricanes. The most intense known Category 4 storm in the eastern Pacific was 2014's Odile. The lowest pressure of this storm was 918 millibars, lower than that of some Category 5's, such as Guillermo.
Hurricanes have reached Category 5 intensity during every month from June to October. The earliest Category 5 to form in a season is 1973's Hurricane Ava, which formed on June 7. The latest Category 5 to form in a season is Hurricane Kenna, which reached peak intensity on October 24. Hurricanes Ava, Gilma, Ioke, Linda, and Patricia are the most intense storms to form in their respective months. There have been no May, November, or off-season Category 5 hurricanes.
Two Pacific hurricanes are known to have reached Category 5 intensity multiple times: Emilia and Ioke. Both did it twice, and Ioke reached Category 5 status a third time as a typhoon while in the western Pacific. Hurricane Ioke was tied for the longest-lasting Category 5 hurricane recorded, spending 42 hours at that strength, while hurricanes John and Linda had the longest time spent consecutively at that intensity.
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In the eastern Pacific, Category 5 hurricanes usually occur only in El Niño years. During El Niño years, conditions are more favorable for tropical cyclones because of warmer sea surface temperatures and reduced wind shear. This is why Category 5 hurricanes cluster in single seasons, with half of the known Category 5 hurricanes (nine) having occurred in the 1994, 2002, and 2018 seasons–the three seasons with the most Category 5 hurricanes, at three each. The effects of El Niño are most significant in the central Pacific (140°W to the dateline).
The general lack of Category 5s in non warm-ENSO years is because of there being limited space for development. The prevailing ocean currents of the area carry warm water to the west. As there is no large piece of land to block the water and cause it to "pile up" like in the Atlantic, the area suitable for all tropical cyclones is small. Farther out to sea, while waters are still warm, wind shear limits the development of tropical cyclones in the waters south of Hawaii. This makes an otherwise ideal region unfavorable for tropical cyclones.
This does not mean that a Category 5 hurricane cannot form outside of an El Niño event. The entire year of 1959 was neither an El Niño or a La Niña, but it had one Category 5 hurricane (Patsy). Most of 1973 was during a La Niña, which reduces tropical cyclone activity in the eastern Pacific, yet Hurricane Ava, a Category 5 hurricane, formed in June of that year. The 2009, 2010, 2014, and 2015 seasons are the only pairs of seasons in which a Category 5 hurricane formed in consecutive years (Rick and Celia, and Marie and Patricia, respectively).
Of all of the Category 5 Pacific hurricanes, the only ones to make landfall at any intensity were Hurricane Kenna, Hurricane Rick, Hurricane Patricia, and Hurricane Willa. None made landfall as Category 5 hurricanes; Patricia and Kenna had weakened to Category 4 status at the time of their landfalls, Willa had weakened to Category 3, and Rick was a tropical storm at its landfall. Patricia was the strongest at landfall among Pacific hurricanes; 1976's Hurricane Madeline and 1992's Hurricane Iniki are tied as the second-strongest storms at landfall, both of which did not reach Category 5 strength, but made landfall as stronger Category 4 storms than Kenna. Originally, a hurricane in 1959 was thought to have struck Manzanillo at Category 5 intensity, but a reanalysis in 2016 indicated the storm had peaked as a Category 4 hurricane, and made landfall with the same sustained wind speed as Kenna. Patricia was also originally thought to have made landfall as a Category 5 hurricane near Manzanillo before post-season analysis in 2016.
In addition to these four systems, hurricanes John, Linda, Ioke, Lane, and Walaka all threatened land at some point during their existence. John, Ioke and Walaka had minimal impacts on Johnston Atoll, John caused heavy surf in Hawaii, and Walaka passed close to East Island in the French Frigate Shoals. 40 inches (1,000 mm) of rain across many areas.Linda was briefly forecast to approach southern California, and it passed close to Socorro Island near peak intensity. Out of the five aforementioned hurricanes, Lane had the most significant impact on land, threatening Hawaii as a major hurricane, and dropping more than
The reason for the lack of landfalls is that tropical cyclones in the northern hemisphere usually travel to the west.In the Atlantic, this sends hurricanes towards North America. In the eastern Pacific, this sends tropical cyclones out into the open ocean to dissipate over waters too cool to support them or in environments with high wind shear. Hawaii, the only heavily populated island chain in the eastern Pacific, is protected from most hurricanes by a subtropical ridge and because its land area is small relative to the total ocean area where hurricanes form and travel.
In meteorology, a cyclone is a large scale air mass that rotates around a strong center of low atmospheric pressure. Cyclones are characterized by inward spiraling winds that rotate about a zone of low pressure. The largest low-pressure systems are polar vortices and extratropical cyclones of the largest scale. Warm-core cyclones such as tropical cyclones and subtropical cyclones also lie within the synoptic scale. Mesocyclones, tornadoes and dust devils lie within smaller mesoscale. Upper level cyclones can exist without the presence of a surface low, and can pinch off from the base of the tropical upper tropospheric trough during the summer months in the Northern Hemisphere. Cyclones have also been seen on extraterrestrial planets, such as Mars and Neptune. Cyclogenesis is the process of cyclone formation and intensification. Extratropical cyclones begin as waves in large regions of enhanced mid-latitude temperature contrasts called baroclinic zones. These zones contract and form weather fronts as the cyclonic circulation closes and intensifies. Later in their life cycle, extratropical cyclones occlude as cold air masses undercut the warmer air and become cold core systems. A cyclone's track is guided over the course of its 2 to 6 day life cycle by the steering flow of the subtropical jet stream.
The 2002 Pacific hurricane season was a slightly above average Pacific hurricane season that saw three tropical cyclones reach Category 5 intensity on the Saffir–Simpson scale, tied for the most in a season with 1994 and 2018. The strongest storm this year was Hurricane Kenna, which reached Category 5 on the Saffir–Simpson scale. It made landfall near Puerto Vallarta, located in the Mexican state of Jalisco, on October 25. Elsewhere, Tropical Storm Julio made landfall in Mexico, and Tropical Storm Boris dumped torrential rain along the Mexican coast, despite remaining offshore.
The 1997 Pacific hurricane season was a very active hurricane season. With hundreds of deaths and hundreds of millions of dollars in damage, this season was one of the costliest and deadliest Pacific hurricane seasons. This was due to the exceptionally strong 1997–98 El Niño event. The 1997 Pacific hurricane season officially started on May 15, 1997, in the eastern Pacific, and on June 1, 1997, in the central Pacific, and lasted until November 30, 1997. These dates conventionally delimit the period of each year when almost all tropical cyclones form in the northeastern Pacific Ocean.
The 1973 Pacific hurricane season was an event in tropical cyclone meteorology. The most important system this year was Hurricane Ava, which was the most intense Pacific hurricane known at the time. Several other much weaker tropical cyclones came close to, or made landfall on, the Pacific coast of Mexico. The most serious of these was Hurricane Irah, which downed power and communication lines in parts of the Baja California Peninsula; the other landfalling storms caused rain and some flooding. No tropical cyclone this season caused any deaths.
The 1884 Atlantic hurricane season was one of only three Atlantic hurricane seasons, along with 1852 and 1858, in which every known tropical cyclone attained hurricane status. Overall, four tropical cyclones developed, three of which made landfall. The first system was initially observed over the northwestern Atlantic Ocean on September 1. It struck Newfoundland the following day, but impact there is unknown. On September 3, the next hurricane developed, though it did not affect land in its duration. The third hurricane struck Georgia, accompanied by damaging waves in north Florida.
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, central, and western, while the southern Pacific is divided into 2 sections, the Australian region 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.
Tropical cyclones are ranked on one of five tropical cyclone intensity scales, according to their maximum sustained winds and which tropical cyclone basin(s) they are located in. Only a few scales of classifications are used officially by the meteorological agencies monitoring the tropical cyclones, but some alternative scales also exist, such as accumulated cyclone energy, the Power Dissipation Index, the Integrated Kinetic Energy Index, and the Hurricane Severity Index.
An Atlantic hurricane or tropical storm is a tropical cyclone that forms in the Atlantic Ocean, usually between the months of June and November. A hurricane differs from a cyclone or typhoon only on the basis of location. A hurricane is a storm that occurs in the Atlantic Ocean and northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean, and a cyclone occurs in the south Pacific or Indian Ocean.
The 1959 Pacific hurricane season featured the first Category 5 hurricane ever recorded in the Central Pacific basin.
Traditionally, areas of tropical cyclone formation are divided into seven basins. These include the north Atlantic Ocean, the eastern and western parts of the northern Pacific Ocean, the southwestern Pacific, the southwestern and southeastern Indian Oceans, and the northern Indian Ocean. The western Pacific is the most active and the north Indian the least active. An average of 86 tropical cyclones of tropical storm intensity form annually worldwide, with 47 reaching hurricane/typhoon strength, and 20 becoming intense tropical cyclones, super typhoons, or major hurricanes.
Hurricane Ava was one of the strongest tropical cyclones ever recorded in the northeastern Pacific Ocean. It was the first named storm of the 1973 Pacific hurricane season. Forming in early June, Hurricane Ava eventually reached Category 5 intensity on the Saffir-Simpson Hurricane Scale, the first Pacific hurricane to do so in June and the earliest ever in a season. Its central pressure made it the most intense known Pacific hurricane at the time. Despite its intensity, Hurricane Ava stayed at sea without significant impact.