Ava near peak intensity on June 6 | |
Meteorological history | |
---|---|
Formed | June 2,1973 |
Dissipated | June 12,1973 |
Category 5 major hurricane | |
1-minute sustained (SSHWS/NWS) | |
Highest winds | 160 mph (260 km/h) |
Lowest pressure | 915 mbar (hPa);27.02 inHg |
Overall effects | |
Fatalities | None |
Damage | None |
Areas affected | California |
IBTrACS | |
Part of the 1973 Pacific hurricane season |
Hurricane Ava was the earliest forming Category 5 hurricane on record in the East Pacific basin. The storm is also tied with 2006's Hurricane Ioke as the fifth-strongest Pacific hurricane on record. 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,Ava stayed at sea without significant impact.
Ava was given the most advanced measurement and reconnaissance available at the time. Recon flights were conducted and meteorological equipment was tested. The hurricane was also photographed from space by satellites and Skylab astronauts.
On June 2, 1973, a tropical depression formed about 250 miles (400 km) south of Salina Cruz, Oaxaca. It started out nearly stationary, and became a tropical storm late on the same day it formed, the first named storm of the 1973 Pacific hurricane season. Ava then slowly moved westwards away from Mexico and became a hurricane on June 3. Ava became a major hurricane on the afternoon of June 5. On the next day, a United States Air Force recon flight measured a wind speed of 150 miles per hour (240 kilometers per hour) and a central pressure of 915 millibars (27.0 inches of mercury). These measurements made Hurricane Ava by far the most intense storm of the season. [1]
At its peak, Ava had winds of 160 mph (260 km/h). [1] These winds made the storm a Category 5 hurricane on the Saffir–Simpson hurricane scale (SSHS), the highest category on the scale, [2] and the first Category 5 hurricane since the 1959 season. [3] Ava was also a hurricane with windspeeds rapidly increasing the closer to the eye they were measured. Over a distance of 4 mi (6.4 km), wind speeds increased from 70 to 158 mph (113 to 254 km/h), and they increased from 105 to 158 mph (169 to 254 km/h) over half that distance. The reading of 915 mbar (27.0 inHg) was roughly 100 mbar (3.0 inHg) lower than the ambient environment far from the storm. [1]
After its peak, Ava started weakening on June 7, as it continued its westward path. Its winds were 140 mph (225 km/h) on June 7 and 115 mph (185 km/h) on the next day. It was no longer a major hurricane after its winds fell to 105 mph (169 km/h) on June 9. Later that day it weakened to a tropical storm. It then weakened to a tropical depression on June 11. The system then turned north and dissipated on June 12. Its remnants then became embedded in the trade winds as a tropical wave. [1]
In terms of how well it was forecast, Ava had the largest error of any cyclone during the season. This 14° error five days out was mainly due to its northward turn when it was a weakening depression. [1]
For a few days, Ava was directly underneath Skylab during its first manned mission. [1] Astronauts acquired photographs of the hurricane, [4] which was big enough for Science Pilot Joseph Kerwin to describe it as "an enormous spiral" that was big enough to dominate the view outside the space station's window and prevent anything else from being seen. [5] Astronauts also provided microwave data through Earth Resources Experiment Package sensors. [4] Skylab also used a scatterometer on the system. [6] Unfortunately, Skylab's scatterometer data was harder to use than normal as it was degraded. [7]
Ava was also underneath the NOAA-2 and Nimbus 5 weather satellites. NOAA-2 provided photographs that were used to estimate Ava's maximum windspeeds. Satellite images were useful throughout the cyclone's existence, as did the wind reports of three ships when Ava was a young tropical storm. [1] Nimbus 5 carried an Electrically Scanning Microwave Radiometer and Temperature-Humidity Infrared Radiometer. [8] Both were used to study Ava. The main data provided by the THIR was data indicating cloud temperatures. The ESMR's main data was on rainfall rates, densities, and distributions. The observations also provided confirmation that clouds that are not vertically developed very much can produce tropical rainfall. [9]
Recon aircraft also penetrated Hurricane Ava. It was the first Pacific hurricane penetrated by National Oceanographic and Atmospheric Administration aircraft, [10] but not by aircraft from other agencies. [11] NOAA craft were laden with sensors and measured wave heights reaching 40 feet (12 metres) with a microwave radar system and a laser altimeter. [1] That was the first time ever that sea conditions in a tropical cyclone had been measured that way. [1] United States Air Force planes measured central pressure, air temperature, and humidity in the eye pressures using dropsondes. [1] The collection of data from both space and the air was done in order to allow comparisons. [12] Collectively, all of this measuring made Hurricane Ava the best-measured northeastern Pacific tropical cyclone at the time. [1]
Most intense Pacific hurricanes [3] | |||||
---|---|---|---|---|---|
Rank | Hurricane | Season | Pressure | ||
hPa | inHg | ||||
1 | Patricia | 2015 | 872 | 25.75 | |
2 | Linda | 1997 | 902 | 26.64 | |
3 | Rick | 2009 | 906 | 26.76 | |
4 | Kenna | 2002 | 913 | 26.96 | |
5 | Ava | 1973 | 915 | 27.02 | |
Ioke | 2006 | ||||
7 | Marie | 2014 | 918 | 27.11 | |
Odile | |||||
9 | Guillermo | 1997 | 919 | 27.14 | |
10 | Gilma | 1994 | 920 | 27.17 | |
Listing is only for tropical cyclones in the Pacific Ocean north of the equator and east of the International Dateline |
Hurricane Ava stayed at sea. [13] Consequently, no one was killed and there was no reported damage. However, when it was a recently named tropical storm, Ava did cause sustained winds below gale-force to three ships called the Joseph Lykes, Hoegh Trotter, and Volnay. [1] In addition, large ocean waves churned up by Ava created hazardous surf and strong riptides at Southern California beaches on June 9 and June 10. Those waves reached heights of up to 9 ft (2.7 m) at Newport Beach, 6 ft (1.8 m) at Long Beach, and 8 ft (2.4 m) at Seal Beach. Those waves made beaches more hazardous, resulting in double-to-triple the usual contingent of lifeguards throughout Southern California beaches. At Seal Beach and Newport Beach, lifeguards made 35 and 75 rescues, respectively. [14]
When it was active, Hurricane Ava set many records. Several have since been broken, but Ava still holds a few. Ava ceased being a Category 5 hurricane on June 7, 1973. [3] Emilia (1994) reached Category 5 intensity on July 19, 1994. [15] This span of 7,712 days, which Ava began and Emilia ended, is the longest time between successive Category 5 hurricanes in the northeastern Pacific, and anywhere worldwide, in recorded history. When Hurricane Gilma reached Category 5 strength on July 24, also in 1994, it marked the shortest gap between Category 5 Pacific hurricanes recorded. [3] Ava was also a Category 5 hurricane for exactly 24 hours; a record at the time. Hurricane John broke that in the 1994 season, and hurricanes Linda and Ioke also lasted longer, tied with John. [16] In addition, Ava is the strongest June tropical cyclone in the western hemisphere north of the equator. [3] [17]
A spokesperson from the U.S. National Weather Service was quoted as saying that, "Ava had sustained winds of about 180 knots with some gusts at 200 knots when she [ sic ] was peaking". [14] However, the official "Best track" data file and the seasonal summary in the Monthly Weather Review contradict that report and give maximum winds of 140 knots. [1] [3] If Ava's winds were that high, they would one of the highest ever reported in a tropical cyclone anywhere. Like any report of winds that high it is suspect. [18]
At the time, Hurricane Ava's minimum known pressure of 915 mbar (27.0 inHg) was the lowest-known in its basin, making Ava the most intense Pacific hurricane. Ava is now the fifth-most intense, tied with Hurricane Ioke, as hurricanes Patricia, Linda, Rick and Kenna recorded lower pressures. [3] However, Linda's and Rick's pressures were only estimated from satellite imagery, [19] so Ava held the record for lowest measured pressure until Kenna surpassed it in 2002. [20] However, the meteorological record for the eastern north Pacific are unreliable because geostationary satellite observation did not begin until 1966. [19] Ava's pressure record is itself incomplete; Ava was only a Category 4 when its 915 mbar (27.0 inHg) pressure was measured, and the only reading from when it was a Category 5 hurricane is 928 mbar (27.4 inHg). [21] These two factors mean that Ava's lowest pressure may be below 915 mbar (27.0 inHg), and that there may be other cyclones stronger than Ava. [22]
Typhoon Tip, known in the Philippines as Super Typhoon Warling, was an exceptionally large, extremely powerful, and long-lived tropical cyclone that traversed the Western Pacific for 20 days, shattering multiple records worldwide. The forty-third tropical depression, nineteenth tropical storm, twelfth typhoon, and third super typhoon of the 1979 Pacific typhoon season, Tip developed out of a disturbance within the monsoon trough on October 4 near Pohnpei in Micronesia. Initially, Tropical Storm Roger to the northwest hindered the development and motion of Tip, though after the storm tracked farther north, Tip was able to intensify. After passing Guam, Tip rapidly intensified and reached peak sustained winds of 305 km/h (190 mph) and a worldwide record-low sea-level pressure of 870 hPa (25.69 inHg) on October 12. At its peak intensity, Tip was the largest tropical cyclone on record, with a wind diameter of 2,220 km (1,380 mi). Tip slowly weakened as it continued west-northwestward and later turned to the northeast, in response to an approaching trough. The typhoon made landfall in southern Japan on October 19, and became an extratropical cyclone shortly thereafter. Tip's extratropical remnants continued moving east-northeastward, until they dissipated near the Aleutian Islands on October 24.
Hurricane John, also known as Typhoon John, was the farthest-traveling tropical cyclone ever observed worldwide. It was also the longest-lasting tropical cyclone on record globally at the time, until it was surpassed by Cyclone Freddy in 2023. John formed during the 1994 Pacific hurricane season, which had above-average activity due to the El Niño of 1994–1995, and peaked as a Category 5 hurricane on the Saffir–Simpson scale, the highest categorization for hurricanes.
The 1940 Atlantic hurricane season was a generally average period of tropical cyclogenesis in 1940. Though the season had no official bounds, most tropical cyclone activity occurred during August and September. Throughout the year, fourteen tropical cyclones formed, of which nine reached tropical storm intensity; six were hurricanes. None of the hurricanes reached major hurricane intensity. Tropical cyclones that did not approach populated areas or shipping lanes, especially if they were relatively weak and of short duration, may have remained undetected. Because technologies such as satellite monitoring were not available until the 1960s, historical data on tropical cyclones from this period are often not reliable. As a result of a reanalysis project which analyzed the season in 2012, an additional hurricane was added to HURDAT. The year's first tropical storm formed on May 19 off the northern coast of Hispaniola. At the time, this was a rare occurrence, as only four other tropical disturbances were known to have formed prior during this period; since then, reanalysis of previous seasons has concluded that there were more than four tropical cyclones in May before 1940. The season's final system was a tropical disturbance situated in the Greater Antilles, which dissipated on November 8.
Hurricane Linda was an extremely powerful tropical cyclone that was, at the time, the most intense eastern Pacific hurricane on record, until it was surpassed 18 years later by Patricia. Forming from a tropical wave on September 9, 1997, Linda steadily intensified and reached hurricane status within 36 hours of developing. The storm rapidly intensified, reaching sustained winds of 185 mph (295 km/h) and an estimated central pressure of 902 millibars (26.6 inHg); both were records for the eastern Pacific until Hurricane Patricia surpassed them in 2015. The hurricane was briefly forecast to move toward southern California, but instead, it turned out to sea and lost its status as a tropical cyclone on September 17, before dissipating on September 21. Linda was the fifteenth tropical cyclone, thirteenth named storm, seventh hurricane, and fifth major hurricane of the 1997 Pacific hurricane season. Linda was also the most intense tropical cyclone worldwide in 1997.
The 1929 Atlantic hurricane season was a near average season in terms of accumulated cyclone energy, but is among the least active Atlantic hurricane seasons on record in terms of storms forming, with only five tropical cyclones forming. Three of them intensified into a hurricane, with one strengthening further into a major hurricane. The first tropical cyclone of the season developed in the Gulf of Mexico on June 27. Becoming a hurricane on June 28, the storm struck Texas, bringing strong winds to a large area. Three fatalities were reported, while damage was conservatively estimated at $675,000 (1929 USD).
The 1973 Pacific hurricane season was an above average season, with twelve named tropical cyclones in total. Seven storms became hurricanes, of which three were major. The season officially started May 15, 1973, in the eastern Pacific, and June 1, 1973, in the central Pacific, and lasted until November 30, 1973. These dates conventionally delimit the period of each year when most tropical cyclones form in the northeastern Pacific Ocean.
An Atlantic hurricane is a type of tropical cyclone that forms in the Atlantic Ocean primarily between June and November. The terms "hurricane", "typhoon", and "tropical cyclone" can be used interchangeably to describe this weather phenomenon. These storms are continuously rotating around a low pressure center, which causes stormy weather across a large area, which is not limited to just the eye of the storm. They are organized systems of clouds and thunderstorms that originate over tropical or subtropical waters and have closed low-level circulation, and should not be confused with tornadoes, which are just another type of cyclone. They form over low pressure systems. In the North Atlantic and the Eastern Pacific, the term "hurricane" is used, whereas "typhoon" is used in the Western Pacific near Asia. The more general term "cyclone" is used in the rest of the ocean basins, namely the South Pacific and Indian Ocean.
Hurricane Ioke, also referred to as Typhoon Ioke, was a record-breaking, long-lived and extremely powerful tropical cyclone that traversed the Pacific for 17 days, becoming a Category 5 hurricane on the Saffir–Simpson scale on three different occasions. It was the most intense hurricane ever recorded in the Central Pacific, as well as the fifth-most intense Pacific hurricane on record, tied with 1973's Hurricane Ava. It also generated the most accumulated cyclone energy for a single storm, until Cyclone Freddy surpassed its record in 2023. Ioke was the ninth named storm, fifth hurricane, and third major hurricane of the active 2006 Pacific hurricane season.
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 producing anything from cloudiness and mild showers to severe hail, thunderstorms, blizzards, and tornadoes. These types of cyclones are defined as large scale (synoptic) low pressure weather systems that occur in the middle latitudes of the Earth. In contrast with tropical cyclones, extratropical cyclones produce rapid changes in temperature and dew point along broad lines, called weather fronts, about the center of the cyclone.
Hurricane Guillermo was the ninth-most intense Pacific hurricane on record, attaining peak winds of 160 mph (260 km/h) and a barometric pressure of 919 hPa (27.14 inHg). Forming out of a tropical wave on July 30, 1997, roughly 345 mi (555 km) south of Salina Cruz, Mexico, Guillermo tracked in a steady west-northwestward direction while intensifying. The system reached hurricane status by August 1 before undergoing rapid intensification the following day. At the end of this phase, the storm attained its peak intensity as a powerful Category 5 hurricane. The storm began to weaken during the afternoon of August 5 and was downgraded to a tropical storm on August 8. Once entering the Central Pacific Hurricane Center's area of responsibility, Guillermo briefly weakened to a tropical depression before re-attaining tropical storm status. On August 15, the storm reached an unusually high latitude of 41.8°N before transitioning into an extratropical cyclone. The remnants persisted for more than a week as they tracked towards the northeast and later south and east before being absorbed by a larger extratropical system off the coast of California on August 24.
The 1917 Nueva Gerona hurricane was the most intense tropical cyclone to strike the Florida Panhandle until Hurricane Opal in 1995. The eighth tropical cyclone and fourth tropical storm of the season, this system was identified as a tropical storm east of the Lesser Antilles on September 20. After crossing the Lesser Antilles, the system entered the Caribbean Sea and achieved hurricane intensity on September 21. After becoming a Category 2 hurricane, the storm struck the northern coast of Jamaica on September 23. Early on September 25, the cyclone reached Category 4 status and attained maximum sustained winds of 150 mph (240 km/h) soon thereafter. Later that day, the hurricane made landfall in eastern Pinar del Río Province, Cuba. The system entered the Gulf of Mexico shortly thereafter and weakened slightly. Recurving to the northeast, the hurricane briefly threatened Louisiana before turning toward Florida. Early on September 29, the hurricane made landfall near Fort Walton Beach, Florida, with winds of 115 mph (185 km/h). Once over land, the cyclone rapidly weakened and transitioned into an extratropical cyclone before dissipating on September 30.
During 2010, with only 64 named systems, was considered as one of the least active years for tropical cyclones on record. During the year, tropical cyclones formed within seven different tropical cyclone basins, located within various parts of the Atlantic, Pacific and Indian Oceans. During the year, a total of 111 tropical cyclones developed, with 64 of them being named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC). The most active basin was the North Atlantic, which documented 19 named systems, while the North Indian Ocean, despite only amounting to five named systems, was its basin's most active since 1998. Conversely, both the West Pacific typhoon and East Pacific hurricane seasons experienced the fewest cyclones reaching tropical storm intensity in recorded history, numbering 14 and 8, respectively. Activity across the southern hemisphere's three basins—South-West Indian, Australian, and South Pacific—was spread evenly, with each region recording 7 named storms apiece. The southern hemisphere's strongest tropical cyclone was Cyclone Edzani, which bottomed out with a barometric pressure of 910 mbar in the South-West Indian Ocean. Nineteen Category 3 tropical cyclones formed, including four Category 5 tropical cyclones in the year. The accumulated cyclone energy (ACE) index for the 2010, as calculated by Colorado State University was 573.8 units.
Severe Tropical Cyclone Joan was an intense tropical cyclone that ravaged areas of Western Australia. Forming out of a tropical low on 30 November 1975, Joan gradually intensified as it tracked towards the west. After attaining Category 5 intensity on 5 December, the storm abruptly began to track southward and accelerated. The following day, the cyclone reached its peak intensity with winds of 215 km/h (130 mph) and a barometric pressure of 915 hPa (27.02 inHg). Joan only weakened slightly before making landfall in the vicinity of Mundabullagana. The cyclone rapidly weakened after landfall before dissipating over Western Australia on 12 December.
The 1953 Pacific hurricane season was the least active season on record. The season officially began on May 15 in the northeast Pacific Ocean and on June 1 in the central northern Pacific. They ended on November 30. These dates conventionally delimit the time of year when most tropical cyclones form in northeast Pacific Ocean. Before the satellite age started in the 1960s, data prior to that time on Pacific hurricanes is extremely unreliable as most east Pacific storms are of no threat to land.
Hurricane Patricia was the most intense tropical cyclone ever recorded in the Western Hemisphere and the second-most intense worldwide in terms of barometric pressure. It also featured the highest one-minute maximum sustained winds ever recorded in a tropical cyclone. Originating from a sprawling disturbance near the Gulf of Tehuantepec in mid-October 2015, Patricia was first classified a tropical depression on October 20. Initial development was slow, with only modest strengthening within the first day of its classification. The system later became a tropical storm and was named Patricia, the twenty-fourth named storm of the annual hurricane season. Exceptionally favorable environmental conditions fueled explosive intensification on October 22. A well-defined eye developed within an intense central dense overcast and Patricia grew from a tropical storm to a Category 5 hurricane in just 24 hours—a near-record pace. The magnitude of intensification was poorly forecast and both forecast models and meteorologists suffered from record-high prediction errors.
Hurricane Matthew was the first Category 5 Atlantic hurricane since Felix in 2007 and the southernmost Category 5 Atlantic hurricane on record. The system originated from a tropical wave that emerged off the west coast of Africa on September 22, and ultimately dissipated as an extratropical cyclone near Atlantic Canada on October 10. Late on September 29, it began a period of explosive intensification that brought it to Category 5 strength early on October 1. It weakened slightly and remained a Category 4 until its landfalls in Haiti and Cuba, afterwards it traversed through the Bahamas and paralleled the coast of Florida until making landfall in South Carolina as a Category 1 hurricane. Matthew later transitioned into a post-tropical cyclone on October 10.
During 1996, tropical cyclones formed within seven different tropical cyclone basins, located within various parts of the Atlantic, Pacific, and Indian Oceans. During the year, a total of 139 tropical cyclones formed in bodies of water known as tropical cyclone basins. 90 of them were named by various weather agencies when they attained maximum sustained winds of 35 knots. The strongest tropical cyclone of the year was Cyclone Daniella, peaking with a pressure of 915 hPa (27.02 inHg) in the open waters of the Indian Ocean. Hurricane Fran and Typhoon Herb tie for the costliest storm of the year, both with a damage cost of $5 billion. The deadliest tropical cyclone of the year was the 1996 Andhra Pradesh cyclone, which was blamed for over 1,000 fatalities as it directly affected the state of Andhra Pradesh in India. Five Category 5 tropical cyclones were formed in 1996. The accumulated cyclone energy (ACE) index for the 1996, as calculated by Colorado State University was 960 units.
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