The 1975 Pacific hurricane season officially started May 15, 1975, in the eastern Pacific, and June 1, 1975, in the central Pacific, and lasted until November 30, 1975. These dates conventionally delimit the period of each year when most

tropical cyclone A tropical cyclone is a rapidly rotating storm system with a low-pressure area, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its locat ...

s form in the northeast

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

. The 1975 Pacific hurricane season was slightly above average, with 17 tropical storms forming. Of these, 9 became hurricanes, and 4 became major hurricanes by reaching Category 3 or higher on the Saffir-Simpson Hurricane Scale. The only notable storms are Hurricane Olivia, which killed 30 people, caused $30 million (1975 USD) in damage, and left thousands homeless when it made landfall in October; and an unnamed hurricane that developed at very high latitude, but had no effect on land. Hurricane Denise was the strongest storm of the year. Hurricanes Lily and Katrina passed close to

Socorro Island Socorro Island () is a volcanic island in the Revillagigedo Islands, a Mexican possession lying off the country's western coast. The size is , with an area of . It is the largest of the four islands of the Revillagigedo Archipelago. The last e ...

and Tropical Storm Eleanor made landfall in

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. Hurricane Agatha sank a ship. __TOC__

Season summary

The season began with the formation of Tropical Depression One on June 2 and ended with the extratropical transition of Tropical Storm Priscilla on November 7. No named systems formed in May, two in June, four in July, six in August, three in September, one in October, and one in November. The total length of the season, from the formation of the first depression to the dissipation of the last, was 158 days. In the eastern Pacific (east of 140°W), sixteen tropical storms and eight hurricanes formed. Four of the hurricanes became major hurricanes by reaching Category 3 or higher on the Saffir-Simpson Hurricane Scale. These numbers are close to the long-term averages of fifteen tropical storms, nine hurricanes, and four major hurricanes. There were also four unnamed tropical depressions. The only system to enter or form in the central Pacific (between 140°W and the

international dateline The International Date Line (IDL) is the line extending between the South Pole, South and North Poles that is the boundary between one calendar day and the next. It passes through the Pacific Ocean, roughly following the 180th meridian, 180.0� ...

) was an unusual high-latitude hurricane (north of 30°N), which went unnamed. This was the first occurrence on record of a mid-Pacific upper tropospheric low developing into a tropical cyclone, and the first hurricane on record within the central Pacific north of Hawaii. The only systems to make landfall this year were Tropical Storm Eleanor and Hurricane Olivia. Besides these two systems, Hurricane Agatha caused the sinking of a ship carrying millions of dollars worth of cargo. Tropical Storm Eleanor caused no serious impact. The most devastating storm of the season was Hurricane Olivia. A late-season major hurricane, Olivia came ashore near

Mazatlán Mazatlán () is a city in the Mexican list of states of Mexico, state of Sinaloa. The city serves as the municipal seat for the surrounding , known as the Mazatlán Municipality. It is located on the Pacific Ocean, Pacific coast across from th ...

. The storm killed 30 people, left around 30,000 people homeless, and caused 20 million dollars (1975

USD The United States dollar (symbol: $; currency code: USD) is the official currency of the United States and several other countries. The Coinage Act of 1792 introduced the U.S. dollar at par with the Spanish silver dollar, divided it int ...

) in damage.

Systems

Hurricane Agatha

An area of disturbed weather about southwest of

Acapulco Acapulco de Juárez (), commonly called Acapulco ( , ; ), is a city and Port of Acapulco, major seaport in the Political divisions of Mexico, state of Guerrero on the Pacific Coast of Mexico, south of Mexico City. Located on a deep, semicirc ...

formed on June 1. It organized into a tropical depression the next day. After heading southwestward, it turned to the northwest and strengthened into Tropical Storm Agatha on June 2. Agatha maintained its course and steadily intensified. It reached hurricane intensity on June 3 while located about southwest of

Zihuatanejo Zihuatanejo (), and/or Ixtapa-Zihuatanejo, is the fourth largest city in the Mexican state of Guerrero. It was known by 18th-century English mariners as Chequetan and/or Seguataneo. Politically the city belongs to the municipalities of Mexico, m ...

. Hurricane Agatha started weakening thereafter, becoming a tropical storm on June 4 and a depression on June 5. It dissipated shortly afterwards. At this time, Agatha was located about south of the Tres Marias Islands. Even though Agatha passed close to Mexico as it weakened, no impact is known to have been caused. Waves caused by Agatha did impact a ship called the ''Polynesian Diakan''. A Greek freighter en route from

Pago Pago Pago Pago ( or ; Samoan language, Samoan: )Harris, Ann G. and Esther Tuttle (2004). ''Geology of National Parks''. Kendall Hunt. Page 604. . is the capital of American Samoa. It is in Maoputasi County, American Samoa, Maoputasi County on Tutuila ...

Terminal Island, California Terminal Island, historically known as , is a largely artificial island located in Los Angeles County, California, between the neighborhoods of Wilmington and San Pedro in the city of Los Angeles, and the city of Long Beach. Terminal Island i ...

, the ''Polynesian Diakan'' began flooding on June 3, forcing the 32-man crew to abandon the vessel. The exact cause of the initial flooding was unknown, but was speculated to be primarily due to

cargo shifting In transportation, cargo refers to goods transported by land, water or air, while freight refers to its conveyance. In economics, freight refers to goods transported at a freight rate for commercial gain. The term cargo is also used in case o ...

and not the weather. The crew was rescued by the

United States Coast Guard The United States Coast Guard (USCG) is the maritime security, search and rescue, and Admiralty law, law enforcement military branch, service branch of the armed forces of the United States. It is one of the country's eight Uniformed services ...

. Three members required hospitalization. After being reached on June 6 by a tugboat in a salvage attempt, the vessel capsized and sank near

San Clemente Island San Clemente Island (Tongva: ''Kinkipar''; Spanish: ''Isla de San Clemente'') is the southernmost of the Channel Islands of California. It is owned and operated by the United States Navy, and is a part of Los Angeles County. It is administer ...

on June 7, taking its multimillion-dollar cargo of 71 containers of canned

tuna A tuna (: tunas or tuna) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bul ...

with it. The reason for the sinking was unknown.

Tropical Storm Bridget

On June 27, a tropical depression formed about south of the tip of the Baja California Peninsula at a location atypical for

tropical cyclogenesis Tropical cyclogenesis is the development and strengthening of a tropical cyclone in the atmosphere. The mechanisms through which tropics, tropical cyclogenesis occur are distinctly different from those through which temperate cyclogenesis occu ...

. The depression moved generally westward, and intensified into Tropical Storm Bridget on June 28. It started accelerating as it turned towards the northwest, then west, and eventually to the southwest. Bridget weakened into a tropical depression on July 2 and dissipated the next day. It remnant circulation hung about in the area for a few more days. Bridget never came near land and thus, no deaths or damage were recorded.

Hurricane Carlotta

A disturbance south of

organized into a tropical depression on July 2. It headed generally west-northwest and steadily intensified, becoming a tropical storm later on July 2. It became a hurricane on July 3 and ultimately peaked as a Category 3 hurricane. Hurricane Carlotta was first major hurricane, Category 3 or higher, of the season. It began weakening thereafter, and was a tropical storm by July 8. Carlotta became a depression on July 10 and dissipated the next day. The hurricane did not come near land and caused no significant impact.

Hurricane Denise

An unstable area developed a circulation and became a tropical depression on July 4. It headed west- northwest and became a tropical storm on July 7. The next day, it was a hurricane and turned to the west. Continuing to strengthen, it reached Category 4 intensity on July 9. This windspeed was the highest of the season. The hurricane turned to the southwest and gradually weakened. By July 11 it was nearly stationary. It then headed northwestward again and continued weakening, becoming a tropical storm on July 13. It weakened into a depression on July 14 and dissipated immediately thereafter. Denise brought winds of near-

gale A gale is a strong wind; the word is typically used as a descriptor in nautical contexts. The U.S. National Weather Service defines a gale as sustained surface wind moving at a speed between .

force to parts of

, but otherwise caused no damage or casualties.

Tropical Storm Eleanor

An area of disturbed weather developed into a tropical depression on July 10, south of

. As its center of circulation became more pronounced and it was upgraded into Tropical Storm Eleanor. The tropical storm moved northwestward, and later curved northward. The system made landfall near Manzanillo on July 12. It quickly dissipated. Eleanor brought winds the Manzanillo, but damage from the storm is minor due to the lack of heavy rains.

Tropical Storm Francene

A rapidly moving

squall A squall is a sudden, sharp increase in wind speed lasting minutes, as opposed to a wind gust, which lasts for only seconds. They are usually associated with active weather, such as rain showers, thunderstorms, or heavy snow. Squalls refer to the ...

y area of disturbed weather that was moving on a northwestward path was upgraded into Tropical Depression Seven on July 27. It intensified into a tropical storm later that day. Francene turned to the west and weakened into a tropical depression on July 28. It slowly weakened and ceased to exist as a

on July 30. Francene's remnants persisted as a tropical disturbance for another twelve hours, before completely dissipating. This tropical cyclone caused no known impact.

Tropical Storm Georgette

An area of disturbed weather about south-southwest of

Cabo San Lucas Cabo San Lucas (, "Luke the Evangelist, Saint Luke Cape (geography), Cape"), also known simply as Cabo, is a Resort town, resort city at the southern tip of the Baja California peninsula, in the Mexican Political divisions of Mexico, state of Baja ...

organized a tropical depression on August 11. It was upgraded to tropical storm intensity the next day. After heading generally westward and peaking as a weak to moderate tropical storm on August 12, Georgette slowly weakened. It weakened into a depression on August 14 and underwent

extratropical transition 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 p ...

thereafter. The cyclone dissipated twelve hours later. Tropical Storm Georgette had no impact on land.

Tropical Storm Hilary

A tropical disturbance formed on August 11 and gradually organized. The next day, an

atmospheric circulation Atmospheric circulation is the large-scale movement of Atmosphere of Earth, air and together with ocean circulation is the means by which thermal energy is redistributed on the surface of the Earth. The Earth's atmospheric circulation varies fro ...

developed. Based on this, this system was classified as Tropical Depression Nine on August 13. The depression quickly intensified into a tropical storm and was named ''Hilary''. The system gradually accelerated to the northwest and reached its peak strength on August 15 with winds of 60 mph (95 km/h). Tropical Storm Hilary then started a gradual weakening trend. It became a depression on August 16, turned a little bit more westward, and dissipated on August 17. Hilary never came near land, and as such caused no death or damage.

Hurricane Ilsa

On August 18, a tropical depression formed south of the

Gulf of Tehuantepec The Gulf of Tehuantepec () is a large body of water on the Pacific coast of the Isthmus of Tehuantepec, southeastern Mexico, at . Many (but not all) Pacific hurricanes form in or near this body of water. A strong, gale-force wind called the T ...

from 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 ...

that had entered the Pacific Ocean from the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

. It strengthened into a tropical storm later that day. The tropical storm moved westward, and became a hurricane on August 21. Ilsa became a

Category 2 hurricane Category, plural categories, may refer to: General uses *Classification, the general act of allocating things to classes/categories Philosophy *Category of being * ''Categories'' (Aristotle) *Category (Kant) *Categories (Peirce) *Category (Vais ...

on August 22. It maintained that intensity for three days as it moved out to sea. On August 25, Ilsa turned westward and rapidly weakened. It fell to tropical storm intensity on August 26. Later that day, while still maintaining winds of

gale A gale is a strong wind; the word is typically used as a descriptor in nautical contexts. The U.S. National Weather Service defines a gale as sustained surface wind moving at a speed between .

-force, Ilsa ceased being a tropical cyclone. Ilsa's remnants continued out over the open

. The remains of Ilsa eventually interacted with another weather system. That triggered the development of the unnamed hurricane of August 31–September 5 Hurricane Ilsa caused no casualties or damage. As the unnamed hurricane formed from Ilsa's remnants, Ilsa and the latter system are unofficially the same tropical cyclone. Indeed, this year's seasonal report from the

Redwood City Redwood City is a city on the San Francisco Peninsula in the Bay Area of Northern California, approximately south of San Francisco and northwest of San Jose. The city's population was 84,292 according to the 2020 census. The Port of Redwo ...

Eastern Pacific Hurricane Center The Eastern Pacific Hurricane Center was formerly the center responsible for forecasting Pacific hurricanes in the eastern north Pacific east of 140°W. It was part of the Weather Bureau Forecast Office San Francisco and was based in Redwood City ...

, in the ''

Monthly Weather Review The ''Monthly Weather Review'' is a peer-reviewed scientific journal published by the American Meteorological Society. It covers research related to analysis and prediction of observed and modeled circulations of the atmosphere, including technique ...

'' includes a brief discussion of the unnamed hurricane in the report's section on Hurricane Ilsa. Neither 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 Pacif ...

nor the official

HURDAT The Hurricane Databases (HURDAT), managed by the National Hurricane Center (NHC), are two separate databases that contain details on tropical cyclones that have occurred within the Atlantic Ocean and Eastern Pacific Ocean since 1851 and 1949 resp ...

"best track" database of tropical cyclone location and intensity data explicitly considers them the same. Hence, as far as official records matter, Ilsa and the unnamed hurricane of August 31 – September 5 are different tropical cyclones.

Hurricane Jewel

On August 24, a tropical depression formed from a tropical disturbance about south of

. It intensified into Tropical Storm Jewel the next day. The

headed generally northwest and paralleled the coast of Mexico. On August 27, Jewel became a hurricane for mere six hours, the minimum possible time in

. Jewel then turned to the west, and then back to the northwest. Jewel weakened to depression strength on August 31. Tropical Depression Jewel dissipated shortly after that, although its remnants remained distinct until September 3. There was no impact.

Hurricane Katrina

On August 29, an area of weather developed directly into a tropical storm, skipping the tropical depression stage. Katrina steadily intensified as it headed west-northwest, gradually turning to the northwest. It peaked in intensity on September 3 as a Category 4 hurricane with winds of , the second highest of the season. Katrina then headed westward and rapidly weakened. It was downgraded into a tropical storm on September 5 and a depression on September 6. The last advisory was issued on September 7 when Katrina dissipated. Although the hurricane brought Category 3-equivalent winds to

on September 2, no damage was reported there or anywhere else.

Unnamed hurricane

The remnants of Hurricane Ilsa interacted with a mid-level trough to produce a new low-level circulation on August 31, about northeast of Hawaii. The new system absorbed the remnants of Ilsa as it moved westward. Thunderstorms increased around the low, resembling a

subtropical cyclone A subtropical cyclone is a weather system that has some characteristics of both tropical cyclone, tropical and extratropical cyclones. As early as the 1950s, meteorologists were uncertain whether they should be characterized as Tropical cyclone ...

by September 1. Its track over warmer waters caused the storm to transition into a tropical storm on September 2, by which time the convection organized into rainbands. By that time, the storm was about north of the Hawaiian island of

Kauai Kauai (), anglicized as Kauai ( or ), is one of the main Hawaiian Islands. It has an area of 562.3 square miles (1,456.4 km2), making it the fourth-largest of the islands and the 21st-largest island in the United States. Kauai lies 73 m ...

. The storm quickly developed a

central dense overcast The central dense overcast, or CDO, of a tropical cyclone or strong subtropical cyclone is the large central area of thunderstorms surrounding its circulation center, caused by the formation of its eyewall. It can be round, angular, oval, or ir ...

, and by 00:00 UTC on September 3 Dvorak classifications began on the cyclone. An approaching cold front turned the storm to the north and northeast. Around that time, the storm developed an eye in the center of the convection, suggesting that it intensified into a hurricane late on September 3, located about south of

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

. It was a small system, measuring about in diameter. A nearby ship reported sustained winds of 63 mph (102 km/h), while another nearby ship reported a pressure of , with a 3-hour tendency increase of , suggesting a minimum pressure of under . After maintaining hurricane status for about 18 hours, the storm weakened due to strong wind shear from the approaching cold front. Early on September 5, the cyclone became

extratropical 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 p ...

in 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 ...

, while located about southwest of

Juneau Juneau ( ; ), officially the City and Borough of Juneau, is the capital of the U.S. state of Alaska, located along the Gastineau Channel and the Alaskan panhandle. Juneau was named the capital of Alaska in 1906, when the government of wha ...

, Alaska. On the same day, the circulation was rapidly absorbed by the frontal system, and the remnants quickly reached the coast of

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

. The remnants of the storm turned southeastward, and the low was last tracked definitively to a point north of

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

Hurricane Lily

Rain and wind reports from the

weather station suggested that a tropical depression was developing. This was confirmed on September 16 from ship reports. It intensified into a tropical storm and was named Lily. Tropical Storm Lily headed northwest in a nearly straight path. By 0000

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

September 18, the system was a moderate tropical storm located about south of Manzanillo Lily was upgraded to hurricane status on the same day and eventually reached its peak strength. After passing southwest of

, Lily weakened, becoming a storm on September 20. Lily weakened into a depression on September 21, turned to the west-southwest, and dissipated. Its remnants remained visible until September 24, when they were no longer distinct via

weather satellite A weather satellite or meteorological satellite is a type of Earth observation satellite that is primarily used to monitor the weather and climate of the Earth. Satellites are mainly of two types: polar orbiting (covering the entire Earth asyn ...

. On September 19, the cyclone brought hurricane-force winds to Socorro Island. No damage or casualties were reported.

Tropical Storm Monica

In late September, three tropical disturbances moved westward across the eastern

. One of them organized into a tropical depression on September 28. The next day the depression was upgraded to Tropical Storm Monica. The tropical storm initially headed west-northwestward and gradually curved towards the north. It reached its peak intensity of 50 mph (85 km/h) on September 29. Monica then gradually weakened. It became a tropical depression on October 1. The cyclone dissipated shortly thereafter. No impact was reported in association with Tropical Storm Monica.

Tropical Storm Nanette

On September 28, a system developed into a tropical depression, simultaneously with Tropical Storm Monica.. It headed generally westward and on September 29, 18 hours after Monica did it, strengthened into a tropical storm. Nanette continued out to sea and slowly strengthened. It peaked in windspeed of 50 mph (85 km/h) on October 3 and turned to the southwest. It then slowly weakened. On October 4, it weakened into a tropical depression and then degenerated into a disturbance that same day. No damage or deaths were reported.

Hurricane Olivia

On October 22, Tropical Depression Eighteen formed from a cluster of three thunderstorms south of Mexico and then strengthened into a tropical storm. It moved northwestward initially, followed by a northeast turn. Olivia then intensified steadily. It reached Category 3 intensity and a peak of 115 mph (185 km/h) winds just before landfall. Early on October 25, Olivia moved ashore just south of

causing major damage. Olivia destroyed 7,000 houses in the region, leaving 30,000 people homeless, and damage totaled $20 million (1975

, $ USD). The hurricane killed 30 people, 20 of them were from drownings in shrimp boats.

Tropical Storm Priscilla

A nearly stationary cloudy area developed a circulation on November 2. The depression drifted north for a while before turning to the west-northwest on November 3. It intensified into a tropical storm on November 4. Priscilla then began turning to the north. However, the system failed to re-curve, instead, the tropical storm turned generally westward. The tropical storm peaked in windspeed as a 65 mph (100 km/h) high-end storm on November 5. It then turned to the northwest on a heading nearly directly at

Clarion Island Clarion Island (), formerly Santa Rosa, is the second largest, westernmost and most remote of Mexico, Mexico's Revillagigedo Islands. The island is located west of Socorro Island and just under from the Mexican mainland. It has an area of an ...

, but it dissipated on November 7 about short of landfall.

Other systems

Besides the tropical storms and hurricanes this season, there were four additional tropical depressions within the eastern Pacific. None of them made landfall anywhere or crossed into the central Pacific. Tropical Cyclone Four formed on July 2 and dissipated the next day. Tropical Cyclone Thirteen formed on September 12 and lasted four days. Tropical Cyclone Seventeen formed October 16 and dissipated a day later. Tropical Cyclone Nineteen formed on November 1 and also dissipated the next day.

Storm names

The following list of names was used for named storms that formed in the North Pacific Ocean east of 140°W in 1975. It was the same list used in the 1971 season. No names were retired following the season; however, an overhaul of the naming system in 1978 to include male names resulted in this list being discarded. The season's unnamed hurricane was the only tropical cyclone reported in the North Pacific between 140°W and the International Date Line in 1975. Had the system been named, it would have been assigned one from the west Pacific's typhoon name list by the

Joint Typhoon Warning Center The Joint Typhoon Warning Center (JTWC) is a joint United States Navy – United States Air Force command in Pearl Harbor, Hawaii. The JTWC is responsible for the issuing of tropical cyclone warnings in the North-West Pacific Ocean, South P ...

Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...

References

External links

Eastern North Pacific Tropical Cyclones of 1975

{{DEFAULTSORT:1975 Pacific Hurricane Season Pacific hurricane seasons Articles which contain graphical timelines