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1971 Pacific hurricane season

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1971 Pacific hurricane season
Season summary map
Seasonal boundaries
First system formedMay 21, 1971
Last system dissipatedNovember 29, 1971
Strongest storm
By maximum sustained windsDenise
 • Maximum winds140 mph (220 km/h)
(1-minute sustained)
 • Lowest pressure951 mbar (hPa; 28.08 inHg)
By central pressureOlivia
 • Maximum winds115 mph (185 km/h)
(1-minute sustained)
 • Lowest pressure948 mbar (hPa; 27.99 inHg)
Seasonal statistics
Total depressions22
Total storms18
Hurricanes12
Major hurricanes
(Cat. 3+)		6
Total fatalities31 total
Total damage$40 million (1971 USD)
Related articles
Pacific hurricane seasons
1969, 1970, 1971, 1972, 1973

The 1971 Pacific hurricane season began on May 15, 1971 in the eastern Pacific (east of 140°W), and on June 1, 1971 in the Central Pacific (from 140°W to the International Date Line); both ended on November 30, 1971. These dates, adopted by convention, historically describe the period in each year when most tropical cyclogenesis occurs in these regions of the Pacific. It was the first year that continuous Weather satellite coverage existed over the entire Central Pacific. As such, this season is often viewed as the start year for modern reliable tropical cyclone data in the Pacific Ocean.[1]

It was an above average pacific hurricane season with 22 tropical cyclones forming, of which 18 became named storms. During the season, 12 storms became hurricanes, of which 6 became major hurricanes by reaching Category 3 or higher on the Saffir-Simpson Hurricane Scale. At the time, this was a single-season record number of storms. This season also had a record 6 systems make landfall: Agatha, Bridget, Katrina, Lily, Olivia and Priscilla.

Systems

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Hurricane Irene-OliviaHurricane Lily (1971)Hurricane Bridget (1971)Saffir–Simpson Hurricane Scale

Hurricane Agatha

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Category 2 hurricane (SSHWS)
 
DurationMay 21 – May 25
Peak intensity100 mph (155 km/h) (1-min);
≤972 mbar (hPa)

On May 21, an area of low pressure developed in the very warm waters south of Tehuantepec, Mexico. Later that day, satellite images showed increasing circulation and Tropical Storm Agatha developed shortly after. Agatha continued moving to the west-northwest parallel to the Mexican coastline and strengthened into a hurricane on May 22. A U.S. Air Force weather reconnaissance aircraft flew into Agatha and found an eye and strong bands. The next day, a reconnaissance plane found winds of 85 to 90 mph (137 to 145 km/h). On May 24, a ship reported winds of 100 mph (160 km/h). Agatha made landfall as a Category 2 hurricane on the Saffir-Simpson hurricane scale within 45 mi (72 km) of Zihuatanejo, Mexico.

The village of Playa Azul was hard hit by the storm. Up to half of the village's homes were destroyed, and much of the banana, mango, and coconut crops were destroyed.

Hurricane Bridget

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Category 2 hurricane (SSHWS)
 
DurationJune 14 – June 20
Peak intensity100 mph (155 km/h) (1-min);
998 mbar (hPa)
Main article: Hurricane Bridget

A tropical disturbance near El Salvador remained unorganized until June 12. The area of convection started to drift west-northwestward and strengthened into Tropical Depression Two-E. On June 15, the Tropical Depression further intensified into Tropical storm status and was named Bridget, the second tropical storm of the season. Tropical Storm Bridget moved across the Gulf of Tehuantepec which was favorable for Development. On June 16, Bridget continued intensifying and satellite imagery and ship report data confirmed that Bridget had strengthened into a hurricane. Hurricane Bridget continued moving west-northwest along the west coast of Mexico and came within 35 to 45 mi (56 to 72 km) of Acapulco on June 17. Bridget later made landfall as a Tropical Storm about 100 mi (160 km) southeast of Manzanillo, Mexico. However, the Tropical Depression Re-entered open waters and dissipated on June 20.

Bridget was the worst hurricane to hit Acapulco in over 25 years; the last strong hurricane to impact Acapulco to a greater extent was the 1943 Mazatlan Hurricane, which made landfall as a Category 3 hurricane and caused $56 million (1971 USD; $421 million 2024 USD) in damage. Hurricane Bridget's storm surge caused flooding in the bay and damaged waterfront and beach facilities. Rough weather and violent seas also sank 20 boats plus a flagship of the Mexican Navy.

Hurricane Carlotta

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Category 1 hurricane (SSHWS)
 
DurationJuly 2 – July 8
Peak intensity85 mph (140 km/h) (1-min);
≤980 mbar (hPa)

On July 1 an area of weather developed about 115 mi (185 km) east of Clipperton Island. On July 2 the area of thunderstorms strengthened into Tropical Storm Carlotta. An Air Force reconnaissance aircraft flew into Carlotta on July 4 and found a system with a well-defined eye and good outflow, but winds only supported a tropical storm. Another reconnaissance plane found winds that were near hurricane strength on July 4. In post-season analysis, it was discovered that Carlotta was a hurricane for 24 hours on July 3 and 4. Later that day, Carlotta started weakening after moving into a less favorable environment. The storm continued to weaken until dissipating on July 8.

Carlotta stayed over open waters during its entire life and no land was affected.

Hurricane Denise

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Category 4 hurricane (SSHWS)
 
DurationJuly 2 – July 14
Peak intensity140 mph (220 km/h) (1-min);
≤951 mbar (hPa)

On July 2 an area of weather got better organized about 865 mi (1,392 km) east of then Tropical Storm Carlotta. On July 4 satellite imagery indicated that the system had strengthened into Tropical Storm Denise and later into Hurricane Denise on July 6. The system continued to move west and on July 7, U.S. Air Force weather reconnaissance plane found a more organized system with sustained winds estimated to be 90 mph (140 km/h) with a minimum central pressure of 963 mbar (hPa; 28.4 inHg). By July 8, the system had sustained one-minute winds of 125 mph (201 km/h) and a minimum central pressure of 951 mbar (951 hPa; 28.1 inHg). Denise reached a peak intensity of 140 mph (230 km/h), a Category 4 on the Saffir-Simpson Hurricane Scale early on July 9, but then started to weaken.

Denise had started a northwest movement towards Hawaii. A reconnaissance aircraft found surface winds of approximately 115 mph (185 mph) on July 9. Soon after, the eyewall started to dissipate, most likely because of cooler inflow. Over the next 48 hours, the system continued to weaken into a tropical storm. On July 13 the system was approaching the Hawaiian Islands, but a reconnaissance flight only found winds that were barely tropical storm strength. What was left of the storm quickly weakened and Denise became a remnant low.

The remnants of Denise moved south of the Hawaiian Islands, but still brought beneficial rains that caused some minor flooding.[2]

Tropical Storm Eleanor

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Tropical storm (SSHWS)
 
DurationJuly 7 – July 11
Peak intensity60 mph (95 km/h) (1-min);
≤1007 mbar (hPa)

Eleanor was a short-lived, weak tropical storm that stayed well out to sea. On July 7, a tropical depression formed east-southeast of the weakening Carlotta and west of the strengthening Denise. By July 8, satellite imagery showed that the depression had strengthened into a tropical storm. Eleanor strengthened over the next 24 hours to a top strength of 60 mph (97 km/h). On July 10, a U.S. Air Force weather reconnaissance plane found a weakening system and the next day the storm was a dissipating depression moving toward the west-southwest.

Hurricane Francene

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Category 3 hurricane (SSHWS)
 
DurationJuly 18 – July 23
Peak intensity115 mph (185 km/h) (1-min);
≤991 mbar (hPa)

An area of enhanced shower activity and low pressure circulation developed a couple hundred miles off the coast of Mexico. On July 18 a tropical depression had formed and on July 19 the system strengthened into Tropical Storm Francene. Francene underwent rapid deepening into a Category 3 hurricane on the Saffir-Simpson Hurricane Scale. However, because of Francene's increasing size, the storm starting pulling in cool surface air which caused weakening. By July 20, Francene had weakened into a tropical storm. Francene continued to weaken over the next 24 hours and was barely a tropical storm by the morning of July 22. That afternoon, Francene began to strengthen once again but it was short-lived. By July 23, the surface circulation had disappeared and Francene was no longer a tropical cyclone. Francene stayed over open water and did not affect land.

Tropical Storm Georgette

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Tropical storm (SSHWS)
 
DurationJuly 20 – July 27
Peak intensity60 mph (95 km/h) (1-min);
990 mbar (hPa)

A tropical depression formed to the east of Hurricane Francene on July 20. A reconnaissance flight found a poorly organized tropical storm with winds of 50 mph (80 km/h) on July 23. Georgette reached a peak intensity of 60 mph (97 km/h) the next day. Ships to the north of Georgette reported weak tropical storm force winds. By July 26 the storm began to weaken rapidly before dissipating the next day.

Hurricane Hilary

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Category 2 hurricane (SSHWS)
 
DurationJuly 26 – August 7
Peak intensity100 mph (155 km/h) (1-min);
≤964 mbar (hPa)

Tropical Storm Hilary developed about 115 mi (185 km) west of Clipperton Island on July 26. Hilary strengthened quickly into a hurricane by July 28 and a recon plane found surface winds of 90 mph (140 km/h) and noted a well-defined eye. The hurricane would peak as a category 2 with sustained winds of 100 mph (160 km/h) on July 30.[3] Hilary weakened slightly as its motion became erratic across the tropical Pacific Ocean. By August 1 the hurricane turned to the northwest towards cooler waters. Hilary weakened into a tropical storm on August 3 after being at hurricane strength for a week.[3] Steady weakening continued over the next four days before dissipating in the Central Pacific.

Hurricane Ilsa

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Category 3 hurricane (SSHWS)
 
DurationJuly 31 – August 8
Peak intensity115 mph (185 km/h) (1-min);
≤978 mbar (hPa)

Hurricane Ilsa formed on July 31 to the south of the Mexican coast. It gradually strengthened into a tropical storm and a hurricane. Ilsa peaked as a Category 3 hurricane before heading further out to sea and weakening. Hurricane Ilsa dissipated on August 8.

Tropical Storm Jewel

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Tropical storm (SSHWS)
 
DurationAugust 6 – August 11
Peak intensity70 mph (110 km/h) (1-min);
993 mbar (hPa)

Tropical Storm Jewel formed near Mexico on August 6. Heading out to sea, it strengthened into a 70 mph (110 km/h) tropical storm. It dissipated on August 11.

Tropical Storm Katrina

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Tropical storm (SSHWS)
 
DurationAugust 8 – August 13
Peak intensity65 mph (100 km/h) (1-min);
1008 mbar (hPa)

Katrina was a very small storm. Katrina brushed Baja California Sur and made landfall in the Mexican state of Sonora as a tropical storm. It dissipated on August 13. Rain from Katrina's remnants ruined crops, destroyed railroad trestles, and washed away three bridges.

Hurricane Lily

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Category 1 hurricane (SSHWS)
 
DurationAugust 28 – September 1
Peak intensity85 mph (140 km/h) (1-min);
978 mbar (hPa)
Main article: Hurricane Lily (1971)

The remnants of Tropical Storm Chloe in the Atlantic formed into Tropical Depression Twelve on August 28. Twelve continued northeast and intensified into a tropical storm and was thus assigned the name Lily. Lily turned northwest. Rapid intensification occurred and Lily developed an eye. Lily peaked with one-minute sustained winds of 85 mph and a pressure of 978mb. Lily made landfall soon after. Once over land, Lily fell below tropical storm intensity. Then the hurricane turned northwest and dissipated soon after.

Hurricane Monica

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Category 3 hurricane (SSHWS)
 
DurationAugust 29 – September 5
Peak intensity115 mph (185 km/h) (1-min);
≤1005 mbar (hPa)

Monica was a Category 3 hurricane which did not affect land.

Hurricane Nanette

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Category 2 hurricane (SSHWS)
 
DurationSeptember 3 – September 9
Peak intensity100 mph (155 km/h) (1-min);
≤984 mbar (hPa)

Hurricane Nanette threatened southern Baja California but turned west before making landfall.

Hurricane Olivia

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Category 3 hurricane (SSHWS)
 
DurationSeptember 20 (Entered basin) – October 1
Peak intensity115 mph (185 km/h) (1-min);
948 mbar (hPa)
Main article: Hurricane Irene–Olivia

Olivia was a continuation of Atlantic Hurricane Irene. Olivia eventually strengthened into a Category 3 hurricane before recurving and making landfall in Baja California as a depression. The remnants of Olivia continued north into California, where they brought rain.

Hurricane Priscilla

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Category 3 hurricane (SSHWS)
 
DurationOctober 6 – October 13
Peak intensity125 mph (205 km/h) (1-min);
951 mbar (hPa)

Priscilla made landfall south of Mazatlán as a tropical storm. It had weakened significantly before landfall, having once been a strong Category 3 hurricane. Priscilla destroyed roughly 36,000 acres of corn, tomatoes, peppers, bananas, and cotton, resulting in $3.12 million in losses. Heavy rains inundated 30 towns in Nayarit, damaging roads and two major thoroughfares; road damage totaled $544,000.[4]

Tropical Storm Ramona

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Tropical storm (SSHWS)
 
DurationOctober 28 – October 31
Peak intensity60 mph (95 km/h) (1-min);
1009 mbar (hPa)

Ramona formed on October 28, it quickly strengthened into a tropical storm. It later weakened back to a tropical depression. Before dissipation, it made a sharp turn to the north-northeast. It had dissipated on October 31.

Tropical Storm Sharon

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Tropical storm (SSHWS)
 
DurationNovember 25 – November 29
Peak intensity40 mph (65 km/h) (1-min);
≤1009 mbar (hPa)

Tropical Storm Sharon was a late season tropical storm that formed a few hundred miles from Mexico on November 25. It slowly strengthened into a minimal tropical storm before unfavorable conditions caused it to dissipate on November 29.

Storm names

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Main articles: Tropical cyclone naming, History of tropical cyclone naming, and List of historical tropical cyclone names

The following list of names was used for named storms that formed in the North Pacific Ocean east of 140°W in 1971.[5] This was the same set of names used for the 1967 season.[6] A storm was named Sharon for the first time this year.[7] No names were retired after this season,[8] thus the same list was used again for the 1975 season.[9]

  • Agatha
  • Bridget
  • Carlotta
  • Denise *
  • Eleanor
  • Francene
  • Georgette
  • Hilary *
  • Ilsa
  • Jewel
  • Katrina
  • Lily
  • Monica
  • Nanette
  • Olivia
  • Priscilla
  • Ramona
  • Sharon
  • Terry (unused)
  • Veronica (unused)
  • Winifred (unused)

Had a named storm formed in the North Pacific between 140°W and the International Date Line in 1971 it would have been assigned a name from the west Pacific's typhoon name list by the Joint Typhoon Warning Center on Guam.[5][7] Named storms in the table above that crossed into the area during the season are noted (*).[10]

Season effects

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This is a table of all of the storms that formed in the 1971 Pacific hurricane season. It includes their name, duration, peak classification and intensities, areas affected, damage, and death totals. Deaths in parentheses are additional and indirect (an example of an indirect death would be a traffic accident), but were still related to that storm. Damage and deaths include totals while the storm was extratropical, a wave, or a low, and all of the damage figures are in 1971 USD.

Saffir–Simpson scale
TD TS C1 C2 C3 C4 C5
1971 Pacific hurricane season statistics
Storm
name 		Dates active Storm category
at peak intensity 		Max 1-min
wind
mph (km/h) 		Min.
press.
(mbar) 		Areas affected Damage
(USD) 		Deaths Ref(s)
Agatha May 21 – 25 Category 2 hurricane 100 (155) 972 Mexico Unknown 0
Bridget June 14 – 20 Category 2 hurricane 100 (155) 998 Mexico 56 17
Carlotta July 2 – 8 Category 1 hurricane 85 (140) 980 None None 0
Denise July 2 – 14 Category 4 hurricane 140 (220) 951 Hawaii None 0
Eleanor July 7 – 11 Tropical storm 60 (95) 1007 None None 0
Francene July 18 – 23 Category 3 hurricane 115 (185) 991 None None 0
Georgette July 20 – 27 Category 1 hurricane 60 (95) 990 None None 0
Hilary July 26 – August 7 Category 2 hurricane 100 (155) 964 None None 0
Ilsa July 31 – August 8 Category 3 hurricane 115 (185) 978 None None 0
Jewel August 6 – 11 Tropical storm 70 (110) 993 None None 0
Katrina August 8 – 13 Tropical storm 65 (100) 1008 Mexico Unknown 0
Lily August 28 – September 1 Category 1 hurricane 85 (140) 978 Mexico Unknown 12-14
Monica August 29 – September 5 Category 3 hurricane 115 (185) 1005 None None 0
Nanette September 3 – 9 Category 2 hurricane 100 (155) 984 Mexico None 0
Olivia September 20 – October 1 Category 3 hurricane 115 (185) 948 Nicaragua, Mexico Unknown 3
Priscilla October 6 – 13 Category 3 hurricane 125 (205) 951 Mexico 3.664 0
Ramona October 28 – 31 Tropical storm 60 (95) 1009 None None 0
Sharon November 25 – 29 Tropical storm 40 (65) 1009 None None 0
Season aggregates
22[nb 1] systems May 21 – November 29   140 (220) 948 Mexico, Nicaragua Unknown 52  

See also

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Notes

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  1. ^ There were four other tropical cyclones which never reached tropical storm strength, but due to the unavailability of their data they are not added onto this table.

References

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  1. ^ "Tropical Cyclone Climatology". College Park, Maryland: NOAA Climate Prediction Center. Retrieved August 15, 2023.
  2. ^ "The 1971 Central Pacific Tropical Cyclone Season". CPHC. 1971. Retrieved 2007-08-22.
  3. ^ a b "Hurricane Hilary track data". Unisys. Archived from the original on 24 July 2008. Retrieved 2008-07-31.
  4. ^ "Storm Damages Mexican Crops". The Corpus Christi Times. Vol. 62, no. 75. Corpus Christi, Texas. Associated Press. October 15, 1971. p. 1D. Retrieved July 26, 2015 – via Newspapers.com. Open access icon
  5. ^ a b National Hurricane Operations Plan (PDF) (Report). Washington, D.C.: NOAA Office of the Federal Coordinator for Meteorological Services and Supporting Research. May 1971. pp. 95, 97. Retrieved February 27, 2024.
  6. ^ 1967 National Hurricane Plan (PDF) (Report). Washington, D.C.: Interdepartmental Committee for Meteorological Services. May 1967. p. 62. Retrieved February 27, 2024.
  7. ^ a b "Eastern North Pacific Tropical Cyclone Name History". Atlantic Tropical Weather Center. Archived from the original on September 29, 2007. Retrieved February 27, 2024.
  8. ^ "Tropical Cyclone Naming History and Retired Names". Miami, Florida: National Hurricane Center. Retrieved February 27, 2024.
  9. ^ National Hurricane Operations Plan (PDF) (Report). Washington, D.C.: NOAA Office of the Federal Coordinator for Meteorological Services and Supporting Research. May 1975. p. 95. Retrieved February 27, 2024.
  10. ^ Pao-Shin Chu; Peng Wu (2008). Climatic Atlas of Tropical Cyclone Tracks over the Central North Pacific (PDF) (Report). University of Hawaii-Manoa. Archived (PDF) from the original on October 23, 2014. Retrieved February 27, 2024.
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