Category 5 hurricanes are tropical cyclone
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 and squalls. Depend ...
s 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 northeastern 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. 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
Typhoon Paka, known in the Philippines as Typhoon Rubing, was the last tropical cyclone of the 1997 Pacific 1997 Pacific hurricane season, hurricane and 1997 Pacific typhoon season, typhoon season, and was among the strongest Pacific typhoons in ...
and
Typhoon Oliwa
Typhoon Oliwa was one of a record eleven super typhoons in the 1997 Pacific typhoon season. It formed in the central Pacific Ocean on September 2 to the southwest of Hawaii, but it became a typhoon in the western Pacific. Oliwa explosively ...
of
1997
File:1997 Events Collage.png, From left, clockwise: The movie set of ''Titanic'', the highest-grossing movie in history at the time; ''Harry Potter and the Philosopher's Stone'', is published; Comet Hale-Bopp passes by Earth and becomes one of t ...
, and
Typhoon Genevieve of
2014
File:2014 Events Collage.png, From top left, clockwise: Stocking up supplies and personal protective equipment (PPE) for the Western African Ebola virus epidemic; Citizens examining the ruins after the Chibok schoolgirls kidnapping; Bundles of wat ...
, which formed east of the dateline but did not reach Category 5 intensity until after crossing the dateline.
Climatology and statistics
The majority of tropical cyclones form and organize in areas of warm
sea surface temperature
Sea surface temperature (SST), or ocean surface temperature, is the ocean temperature close to the surface. The exact meaning of ''surface'' varies according to the measurement method used, but it is between and below the sea surface. Air mass ...
s, usually of at least and low vertical
wind shear
Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal ...
; however, there are outliers to this general rule, such as storms that manage to intensify despite high amounts of vertical wind shear. When a pre-existing tropical disturbance – usually a
tropical wave
A tropical wave (also called easterly wave, tropical easterly wave, and African easterly wave), in and around the Atlantic Ocean, is a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which ...
or a disturbance originating in the
Intertropical Convergence Zone
The Intertropical Convergence Zone (ITCZ ), known by sailors as the doldrums or the calms because of its monotonous windless weather, is the area where the northeast and the southeast trade winds converge. It encircles Earth near the thermal e ...
– enters an area where the aforementioned conditions are present, the disturbance can develop into a tropical cyclone, provided it is far enough from the equator to experience a sufficiently strong
Coriolis force
In physics, the Coriolis force is an inertial or fictitious force that acts on objects in motion within a frame of reference that rotates with respect to an inertial frame. In a reference frame with clockwise rotation, the force acts to the ...
, which causes the counterclockwise rotation of hurricanes in the Northern Hemisphere.
Between the months of December and April, sea surface temperatures in the tropics, where most Northeast Pacific tropical cyclones develop, are usually too low to support significant development. Also, the presence of a
semi-permanent high-pressure area known as the
North Pacific High in the eastern Pacific greatly reduces tropical cyclone development in the winter months, as the North Pacific High results in vertical wind shear that causes environmental conditions to be unconducive to tropical cyclone formation. Another factor preventing tropical cyclones from forming during the winter is the presence of a semi-permanent
low-pressure area
In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible ...
called the
Aleutian Low
The Aleutian Low is a semi-permanent low-pressure system located near the Aleutian Islands in the Bering Sea during the Northern Hemisphere winter. It is a climatic feature centered near the Aleutian Islands measured based on mean sea-level press ...
between January and April. Its effects in the central Pacific near the
160th meridian west
The meridian 160° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole.
The 160th meridian west forms a great ...
cause tropical waves that form in the area to move northward into the
Gulf of Alaska
The Gulf of Alaska (Tlingit: ''Yéil T'ooch’'') is an arm of the Pacific Ocean defined by the curve of the southern coast of Alaska, stretching from the Alaska Peninsula and Kodiak Island in the west to the Alexander Archipelago in the east, ...
. As the disturbances travel northward, they dissipate or transition into an
extratropical cyclone
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low-pressure areas which, along with the anticyclones of high-pressure areas, drive the weather over much of the Earth. Extratropical cyclones are capable of ...
. The Aleutian Low's retreat in late-April allows the warmth of the Pacific High to meander in, bringing its powerful clockwise wind circulation with it. During the month of May, the Intertropical Convergence Zone migrates southward while vertical shear over the tropics decreases. As a result, the earliest tropical waves begin to form,
coinciding with the start of the eastern Pacific hurricane season on May 15.
During summer and early autumn, sea surface temperatures rise further, reaching in July and August, well above the threshold for the formation and intensification of tropical cyclones. This allows for tropical cyclones developing during that time to strengthen significantly, perhaps even
rapidly.
The
El Niño–Southern Oscillation
El Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea te ...
also influences the frequency and intensity of hurricanes in the Northeast Pacific basin. During
El Niño
El Niño (; ; ) is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (approximately between the International Date L ...
events, sea surface temperatures increase in the Northeast Pacific and vertical wind shear decreases. Because of this, an increase in tropical cyclone activity occurs; the opposite happens in the
Atlantic basin
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
during El Niño, where increased wind shear creates an unfavorable environment for tropical cyclone formation. Contrary to El Niño,
La Niña
La Niña (; ) is an oceanic and atmospheric phenomenon that is the colder counterpart of as part of the broader El Niño–Southern Oscillation (ENSO) climate pattern. The name ''La Niña'' originates from Spanish for "the girl", by an ...
events increase wind shear and decreases sea surface temperatures over the eastern Pacific, while reducing wind shear and increasing sea surface temperatures over the Atlantic.
A Category 5 hurricane is defined as having sustained windspeeds of at least over a one-minute period 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
Events January
* January 1 - Cuba: Fulgencio Batista flees Havana when the forces of Fidel Castro advance.
* January 2 - Lunar probe Luna 1 was the first man-made object to attain escape velocity from Earth. It reached the vicinity of E ...
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.
Category 5 Pacific hurricanes
![Patricia 2015-10-23 1730Z (Worldview)](https://upload.wikimedia.org/wikipedia/commons/1/1e/Patricia_2015-10-23_1730Z.jpg)
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
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
coverage in 1966, the number of eastern Pacific tropical cyclones was significantly underestimated.
It is therefore very possible that there are additional Category 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.
The minimum
central pressure
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, 7 ...
of these storms is, for the most part, estimated from satellite imagery using the
Dvorak technique
The Dvorak technique (developed between 1969 and 1984 by Vernon Dvorak) is a widely used system to estimate tropical cyclone intensity (which includes tropical depression, tropical storm, and hurricane/typhoon/intense tropical cyclone intensitie ...
. 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.
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
dropsonde
A dropsonde is an expendable weather reconnaissance device created by the National Center for Atmospheric Research (NCAR), designed to be dropped from an aircraft at altitude over water to measure (and therefore track) storm conditions as the devi ...
s.
[ 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
The Central Pacific Hurricane Center (CPHC) of the United States National Weather Service is the official body responsible for tracking and issuing tropical cyclone warnings, watches, advisories, discussions, and statements for the Central Pacifi ...
, 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 , 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
Hurricane Kenna was the fourth-most intense tropical cyclone on record in the Eastern Pacific basin, and at the time the third-most intense Pacific hurricane to strike the west coast of Mexico. Kenna was the sixteenth tropical depression, thirte ...
, which reached peak intensity on October 24. Hurricanes Ava, Gilma, Ioke, Linda
Linda may refer to:
As a name
* Linda (given name), a female given name (including a list of people and fictional characters so named)
* Linda (singer) (born 1977), stage name of Svetlana Geiman, a Russian singer
* Anita Linda (born Alice Lake i ...
, and Patricia
Patricia is a female given name of Latin language, Latin origin. Derived from the Latin word ''Patrician (ancient Rome), patrician'', meaning "noble"; it is the feminine form of the masculine given name Patrick (given name), Patrick. The name Patr ...
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
Emilia may refer to:
People
* Emilia (given name), list of people with this name
Places
* Emilia (region), a historical region of Italy. Reggio, Emilia
* Emilia-Romagna, an administrative region in Italy, including the historical regions of Emi ...
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.
Landfalls
Of all of the Category 5 Pacific hurricanes, the only ones to make landfall at any intensity were Hurricane Kenna
Hurricane Kenna was the fourth-most intense tropical cyclone on record in the Eastern Pacific basin, and at the time the third-most intense Pacific hurricane to strike the west coast of Mexico. Kenna was the sixteenth tropical depression, thirte ...
, Hurricane Rick, Hurricane Patricia
Hurricane Patricia was the strongest tropical cyclone on record worldwide in terms of wind speed and the second-most intense on record worldwide in terms of pressure, behind Typhoon Tip in 1979, with a minimum atmospheric pressure of 872 mbar ( ...
, and Hurricane Willa
Hurricane Willa was a powerful tropical cyclone that brought torrential rains and destructive winds to southwestern Mexico, particularly the states of Sinaloa and Nayarit, during late-October 2018. It was the twenty-fifth tropical cyclone, twenty ...
. 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.
In addition to these four systems, hurricanes ]John
John is a common English name and surname:
* John (given name)
* John (surname)
John may also refer to:
New Testament
Works
* Gospel of John, a title often shortened to John
* First Epistle of John, often shortened to 1 John
* Secon ...
, Linda
Linda may refer to:
As a name
* Linda (given name), a female given name (including a list of people and fictional characters so named)
* Linda (singer) (born 1977), stage name of Svetlana Geiman, a Russian singer
* Anita Linda (born Alice Lake i ...
, Ioke, Lane
In road transport, a lane is part of a roadway that is designated to be used by a single line of vehicles to control and guide drivers and reduce traffic conflicts. Most public roads (highways) have at least two lanes, one for traffic in each ...
, and Walaka all threatened land at some point during their existence. John, Ioke and Walaka had minimal impacts on Johnston Atoll
Johnston Atoll is an Unincorporated territories of the United States, unincorporated territory of the United States, currently administered by the United States Fish and Wildlife Service (USFWS). Johnston Atoll is a National Wildlife Refuge and ...
, John caused heavy surf in Hawaii
Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...
, and Walaka passed close to East Island in the French Frigate Shoals.[ Linda was briefly forecast to ]approach
Approach may refer to:
Aviation
*Visual approach
*Instrument approach
*Final approach
Music
* ''Approach'' (album), by Von Hertzen Brothers
* ''The Approach'', an album by I:Scintilla
Other uses
*Approach Beach, a gazetted beach in Ting Kau, Ho ...
southern California
Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most po ...
, and it passed close to Socorro Island
Socorro Island ( es, Isla Socorro) is a small volcanic island in the Revillagigedo Islands, a Mexican possession lying off the country's western coast. The size is 16.5 by 11.5 km (10.25 by 7.15 miles), with an area of . It is the largest ...
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 of rain across many areas.
The reason for the lack of landfalls is that tropical cyclones in the northern hemisphere usually travel to the west. Within the Northeast Pacific, the easterly trade winds
The trade winds or easterlies are the permanent east-to-west prevailing winds that flow in the Earth's equatorial region. The trade winds blow mainly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisph ...
cause tropical cyclones to generally move westward out into the open Pacific Ocean. Only rarely do tropical cyclones forming during the peak months of the season make landfall. Closer to the end of the season, the subtropical ridge
The horse latitudes are the latitudes about 30 degrees north and south of the Equator. They are characterized by sunny skies, calm winds, and very little precipitation. They are also known as Subtropics, subtropical ridges, or highs. It is a h ...
steers some storms northwards or northeastwards. Storms influenced by this ridge may bring impacts to the western coasts of Mexico and occasionally even Central America. In the central Pacific basin, the North Pacific High keeps tropical cyclones away from the Hawaiian Islands by forcing them southwards. Combined with cooler waters around the Hawaiian Islands that tend to weaken tropical cyclones that approach them, this makes direct impacts on the Hawaiian Islands by tropical cyclones rare.
See also
*List of tropical cyclones
This is a list of tropical cyclones, subdivided by basin. See the list of tropical cyclone records for individual records set by individual tropical cyclones.
*Lists of Atlantic hurricanes – directory for Atlantic hurricanes north of the equa ...
*List of the most intense tropical cyclones
Winds are often used to measure intensity as they commonly cause notable impacts over large areas, and most popular tropical cyclone scales are organized around sustained wind speeds. However, variations in the averaging period of winds in differ ...
*Pacific hurricane season
A Pacific hurricane is a mature tropical cyclone that develops within the northeastern 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 regio ...
*List of Category 5 Atlantic hurricanes
A Category 5 Atlantic hurricane is a tropical cyclone that reaches Category 5 intensity on the Saffir–Simpson hurricane wind scale, within the Atlantic Ocean to the north of the equator. They are among the strongest tropical cyclones that can ...
* List of Eastern Pacific tropical storms
*List of Category 1 Pacific hurricanes
Category 1 is the lowest classification on the Saffir–Simpson hurricane wind scale, and categorizes tropical cyclones with 1-minute maximum sustained winds between . Tropical cyclones that attain such winds and landfall, move over land whil ...
*List of Category 2 Pacific hurricanes
Category 2 is the fourth-highest classification on the Saffir–Simpson hurricane wind scale, and categorizes tropical cyclones with 1-minute maximum sustained winds between . Tropical cyclones that strengthen to Category 2 status and make ...
*List of Category 3 Pacific hurricanes
Category 3 is the third-highest classification on the Saffir–Simpson hurricane wind scale, and categorizes tropical cyclones with 1-minute maximum sustained winds between . Tropical cyclones that attain such winds and landfall, move over l ...
* List of Category 4 Pacific hurricanes
*List of F5 and EF5 tornadoes
This is a list of tornadoes which have been officially or unofficially labeled as F5, EF5, T10-T11, IF5, or an equivalent rating, the highest possible ratings on the various tornado intensity scales. These scales – the Fujita scale, the Enhance ...
References
{{Category 5 Pacific hurricanes
Category 5
Pacific 5