1974 Pacific hurricane season

1974 Pacific hurricane season
Season summary map
First system formed May 28, 1974
Last system dissipated October 24, 1974
Strongest storm1 Maggie – 934 mbar (hPa) (27.58 inHg), 140 mph (220 km/h) (1-minute sustained)
Total depressions 25
Total storms 18
Hurricanes 11
Major hurricanes (Cat. 3+) 3
Total fatalities 18-33
Total damage Unknown
1Strongest storm is determined by lowest pressure
Pacific hurricane seasons
1972, 1973, 1974, 1975, 1976
Hurricanes Ione(left) and Kirsten (right) undergoing a Fujiwhara interaction in August 1974

The 1974 Pacific hurricane season featured one of the most active periods of tropical cyclones on record with five storms existing simultaneously.[1] The season officially started May 15 in the eastern Pacific, and June 1 in the central Pacific, and lasted until November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the northeast Pacific Ocean.

With seventeen storms, this season was slightly above average. At eleven, the number of hurricanes was also above average. In the central Pacific, one tropical storm formed. Very unusually, on August 26 there were six systems active: Ione, Olive, Kirsten, Lorraine, Joyce, and Maggie. Olive was a Central Pacific storm and had weakened to a tropical depression by this time. The other five were of at least tropical storm intensity simultaneously and remained so until 06Z Aug 27. Five storms were also active 18Z Aug 23-06Z Aug 24.

Season summary

Hurricane Fifi Hurricane Dolores (1974) Saffir-Simpson Hurricane Scale
This weather satellite image (from left to right) of Tropical Cyclones Olive, Ione, Kirsten, Lorraine, and Joyce was taken on August 23, 1974

The overall activity of the 1974 season was near normal, with 25 tropical cyclones developing. Of these storms, 18 were named, 11 became hurricanes and 3 reached major hurricane status. Although the overall number of storms was normal, an exceptionally active period took place from August 19 through September 1. During this two-week span, six storms developed, five of which were active simultaneously on August 23: Ione, Joyce, Kirsten, Lorraine and Olive. Of the season's 447 bulletins, 139 were issued during this period.[1]

Storms

Tropical Storm Aletta

Tropical storm (SSHWS)
Duration May 28 – May 29
Peak intensity 60 mph (95 km/h) (1-min)  992 mbar (hPa)

A tropical disturbance formed to the south of the Gulf of Tehuantepec on May 24; sea surface temperatures (SST's) in the area were around 88 °F (31 °C). The disturbance slowly organized over the next 60 hours, as it was detaching from the Intertropical Convergence Zone (ITCZ). On May 28, Tropical Storm Aletta formed. It recurved to the northeast and made landfall in western Mexico on May 30. Effects were minimal.

Tropical Storm Blanca

Tropical storm (SSHWS)
Duration June 5 – June 8
Peak intensity 60 mph (95 km/h) (1-min)  992 mbar (hPa)

Blanca was a short-lived storm, and did not affect land.

Hurricane Connie

Category 3 hurricane (SSHWS)
Duration June 7 – June 22
Peak intensity 125 mph (205 km/h) (1-min)  942 mbar (hPa)

Hurricane Connie was the first major hurricane. It took a bizarre, twisting path but never made landfall.

Hurricane Dolores

Category 1 hurricane (SSHWS)
Duration June 14 – June 17
Peak intensity 80 mph (130 km/h) (1-min)  973 mbar (hPa)

On June 13, a tropical disturbance south of Mexico showed signs of development. The following day, the system rapidly developed into Tropical Storm Dolores. By June 15, an eye-like feature appeared on satellite imagery as Dolores attained hurricane status. With peak winds of 80 mph (130 km/h), the storm made landfall near Acapulco. Once onshore, Dolores rapidly dissipated and was last noted on June 17.[2]

Across Southwestern Mexico, Hurricane Dolores produced heavy rains that triggered widespread flooding and mudslides. Numerous roads sustained damage, separating communities from surrounding areas.[3] At least 18 people were killed and 32 others were injured by the storm.[4] Additionally, an estimated 173,000 people were affected across the country.[5]

Tropical Storm Eileen

Tropical storm (SSHWS)
Duration June 30 – July 3
Peak intensity 40 mph (65 km/h) (1-min)  997 mbar (hPa)

In late June, a tropical disturbance developed well to the southwest of Mexico. By June 30, sufficient convection had developed over a newly formed area of low pressure to warrant advisories on a tropical depression.[2] Tracking northward,[6] the system gradually attained tropical storm intensity. Due to the lack of direct observations, Eileen's intensity was based solely off satellite estimates;[2] these estimates indicated the cyclone to have attained peak winds of 40 mph (65 km/h) and a minimum pressure of 997 mbar (hPa; 29.44 inHg).[1] By July 2, Eileen entered a region of stable air, causing convection to diminish. The storm degenerated into a non-convective low late on July 3 as it turned northwestward.[2] The remnants of Eileen were last noted on July 4 well to the southwest of the southern tip of Baja California.[6]

Hurricane Francesca

Category 1 hurricane (SSHWS)
Duration July 14 – July 19
Peak intensity 80 mph (130 km/h) (1-min)  973 mbar (hPa)

Francesca was a category 1 hurricane. It neared Baja California by the 17th but turned away before striking.

Hurricane Gretchen

Category 2 hurricane (SSHWS)
Duration July 17 – July 21
Peak intensity 100 mph (155 km/h) (1-min)  982 mbar (hPa)

Gretchen was a category 2 hurricane that threatened southern Baja California, but it turned away without affecting land.

Tropical Storm Helga

Tropical storm (SSHWS)
Duration August 10 – August 13
Peak intensity 45 mph (75 km/h) (1-min)  990 mbar (hPa)

Helga was a storm that did not affect land.

Hurricane Ione

Category 3 hurricane (SSHWS)
Duration August 20 – August 31
Peak intensity 115 mph (185 km/h) (1-min)  954 mbar (hPa)

On August 19, a tropical disturbance was identified near the Intertropical Convergence Zone well to the east-southeast of Hawaii. The next morning, the system developed into a tropical depression as it tracked towards the west-northwest. Later on August 20, the depression intensified into Tropical Storm Ione. However, cold air from a nearby stratocumulus field became entrained in Ione's circulation, causing it to weaken to a depression 24 hours later. Now moving towards the west-southwest, the system remained weak for nearly two days. On August 23, Ione rapidly intensified as convection deepened and an eye feature appeared on satellite imagery. The storm subsequently attained hurricane status that evening before crossing 140°W and entering the Central Pacific.[2]

Intensification slowed on August 24 as Ione attained winds in excess of 100 mph (155 km/h). Over the next day, the system turned northward and attained its peak intensity late on August 25 with winds of 115 mph (185 km/h).[7] Additionally, the storm attained an estimated minimum central pressure of 954 mbar (hPa; 28.17 inHg).[1] Shortly after reaching this intensity, Ione weakened as it began a U-shaped curve, tracking northeast before turning towards the southwest. During the afternoon of August 27, the system was downgraded to a tropical storm. By August 29, Ione further weakened to a tropical depression and acquired a westward track before dissipating south of Hawaii on August 31.[7]

Tropical Storm Olive

Tropical storm (SSHWS)
Duration August 22 – August 25
Peak intensity 45 mph (75 km/h) (1-min)  1009 mbar (hPa)

On August 21, just one day after Ione formed, another disturbance formed along the ITCZ and developed into a tropical depression the following day. Tracking generally towards the west, the system slowly organized. By August 23, the depression intensified into Tropical Storm Olive well to the south of Hawaii. Olive briefly attained winds of 45 mph (75 km/h) before weakening to a tropical depression on August 24. Convection waned for the next 30 hours and Olive degenerated into a disturbance on August 25. The remnant vortex of the storm was last noted on August 26 roughly 210 mi (340 km) southeast of Johnston Island.[7]

Hurricane Joyce

Category 1 hurricane (SSHWS)
Duration August 22 – August 27
Peak intensity 85 mph (140 km/h) (1-min)  973 mbar (hPa)

Joyce was a weak hurricane that did not affect land.

Hurricane Kirsten

Category 1 hurricane (SSHWS)
Duration August 22 – August 29
Peak intensity 85 mph (140 km/h) (1-min)  973 mbar (hPa)

Hurricane Kirsten took an erratic path. After traveling northwest for a while, it reversed direction and backtracked to almost where it started. It then reversed direction again and underwent a Fujiwhara interaction with Hurricane Ione.

Tropical Storm Lorraine

Tropical storm (SSHWS)
Duration August 23 – August 28
Peak intensity 50 mph (85 km/h) (1-min)  987 mbar (hPa)

Tropical Storm Lorraine took an erratic, Z-shaped path during its life. It formed on August 23 and dissipated August 28.

Hurricane Maggie

Category 4 hurricane (SSHWS)
Duration August 26 – September 1
Peak intensity 140 mph (220 km/h) (1-min)  928 mbar (hPa)

Hurricane Maggie was the strongest storm of the season. It reached Category 4 but never threatened land.

Hurricane Norma

Category 1 hurricane (SSHWS)
Duration September 9 – September 10
Peak intensity 75 mph (120 km/h) (1-min)  987 mbar (hPa)

On September 7, a large area of thunderstorms was identified southwest of Mexico. Over the following two days, the system gradually organized as it moved northwest and was declared a tropical depression on September 9. Upon being classified a depression, the storm acquired a more northerly track and soon attained tropical storm status. The newly christened Tropical Storm Norma maintained a general northward track towards Mexico.[2] On September 10, Norma briefly strengthened into a hurricane, with peak winds estimated at 75 mph (120 km/h) before making landfall west of Acapulco.[1][6] Within hours of moving onshore, the storm rapidly deteriorated and dissipated later that day.[2]

Heavy rains produced by Norma triggered mudslides in and around Acapulco, resulting in three fatalities.[1]

Hurricane Fifi–Orlene

Category 2 hurricane (SSHWS)
Duration September 21 – September 24
Peak intensity 105 mph (165 km/h) (1-min)  978 mbar (hPa)

Orlene was a part of Hurricane Fifi. Fifi weakened to a depression and crossed into the east Pacific. The system restrengthened and was renamed Tropical Storm Orlene. Orlene hugged the coast before recurving to the northeast and made landfall shortly after reaching Category 2 intensity.

Hurricane Patricia

Category 1 hurricane (SSHWS)
Duration October 4 – October 15
Peak intensity 90 mph (150 km/h) (1-min)  964 mbar (hPa)

On October 3, an area of disturbed weather was identified several hundred miles southwest of El Salvador. Over the following day, an area of low pressure developed within the disturbance and was subsequently declared a tropical depression. Tracking west-northwestward, the depression eventually intensified into Tropical Storm Patricia on October 6 in light of a significant in convection. The next day, a ragged eye developed and the storm strengthened into a hurricane. Intensification continued through the evening of October 9,[2] at which time Patricia attained its peak intensity with winds estimated at 90 mph (150 km/h).[nb 1][1] Within a day of peaking, the hurricane turned southwestward and weakened. Gradual degradation of the storm took place over the next few days with little convection present over the system by October 11. By then, Patricia had weakened to a tropical depression. On October 15, Patricia was declassified a tropical cyclone as only a low-level circulation devoid of convection remained.[2] The remnants of the storm were last noted on October 17 well to the east-southeast of Hawaii.[6]

Tropical Storm Rosalie

Tropical storm (SSHWS)
Duration October 20 – October 24
Peak intensity 65 mph (100 km/h) (1-min)  987 mbar (hPa)

On October 18, pronounced thunderstorm activity developed along the ITCZ. Gradually, a tropical disturbance formed within this region well to the west-southwest of Mexico. During the morning of October 20, convection rapidly increased and the system was classified as Tropical Storm Rosalie. Visible satellite imagery revealed only an "oval-shaped" area of thunderstorms with no banding features.[2] Tracking generally towards the west-southwest, Rosalie attained its peak intensity with winds estimated around 65 mph (100 km/h) on October 21.[6] Later that day, the system neared an area of more stable air.[2] Gradual weakening ensued over the following days, with Rosalie degrading to tropical depression status on October 23.[6] Void of convection, the remnant swirl of Rosalie was last noted on October 24 well to the southeast of Hawaii.[2][6]

Other storms

In addition to the eighteen named storms, there were seven tropical depression during the course of the season.[1]

1974 storm names

The following names were used for named storms that formed in the eastern Pacific in 1974. It is the same list as the 1970 season, except for Aletta, which replaced Adele. This is the last time this list was used to name storms, as modern naming began in 1978. Despite this, the names Aletta, Blanca, Dolores, Orlene, Patricia and Selma were put on modern naming lists.

  • Aletta
  • Blanca
  • Connie
  • Dolores
  • Eileen
  • Francesca
  • Gretchen
  • Helga
  • Ione
  • Joyce
  • Kirsten
  • Lorraine
  • Maggie
  • Norma
  • Orlene
  • Patricia
  • Rosalie
  • Selma (unused)
  • Toni (unused)
  • Viviam (unused)
  • Winona (unused)

In this season, the Central Pacific named storms from the western Pacific’s typhoon list. One name, Olive, was used.

Season effects

This is a table of all of the storms in the 1974 Pacific hurricane season. It includes their durations, peak intensities, names, landfall(s), damages, and death totals. Deaths in parentheses are additional and indirect (an example of an indirect death would be a traffic accident), but are still storm-related. Damage and deaths include totals while the storm was extratropical or a wave or a low. All of the damage figures are in 1974 USD.

Saffir–Simpson hurricane wind scale
TD TS C1 C2 C3 C4 C5
1974 Pacific hurricane statistics
Storm
name		 Dates active Storm category

at peak intensity

 Max 1-min
wind
mph (km/h)		 Min.
press.
(mbar)		 Areas affected Damage
(millions USD)		 Deaths
Aletta May 28 – 29 Tropical storm 60 (95) 992 None None 0
Blanca June 5 – 8 Tropical storm 60 (95) 992 None None 0
Connie June 7 – 22 Category 3 hurricane 125 (205) 942 None None 0
Dolores June 14 – 17 Category 1 hurricane 80 (130) 973 Southwestern Mexico (Guerrero) 4 18 – 28
Eileen June 30 – July 3 Tropical storm 40 (65) 997 None None 0
Depression July 9 – 13 Tropical depression 35 (55) N/A None None 0
Francesca July 14 – 19 Category 1 hurricane 80 (130) 973 None None 0
Gretchen July 17 – 21 Category 2 hurricane 100 (155) 987 None None 0
Depression July 18 – 20 Tropical depression 35 (55) N/A None None 0
Depression July 21 – 26 Tropical depression 35 (55) N/A None None 0
Depression July 31 – August 11 Tropical depression 35 (55) 1001 None None 0
Depression August 5 – 7 Tropical depression 35 (55) N/A None None 0
Helga August 10 – 13 Tropical storm 45 (75) 990 None None 0
Ione August 20 – 31 Category 3 hurricane 115 (185) 954 None None 0
Olive August 22 – 25 Tropical storm 45 (75) 1009 None None 0
Joyce August 22 – 27 Category 1 hurricane 85 (140) 973 None None 0
Kirsten August 22 – 29 Category 1 hurricane 85 (140) 973 None None 0
Lorraine August 23 – 28 Tropical storm 50 (85) 987 None None 0
Maggie August 26 – September 1 Category 4 hurricane 140 (220) 928 None None 0
Depression September 3 – 7 Tropical depression 35 (55) 1001 None None 0
Norma September 9 – 10 Category 1 hurricane 75 (120) 978 Southwestern Mexico (Guerrero) N/A 3
Orlene September 21 – 24 Category 2 hurricane 105 (165) 987 Southwestern Mexico, Western Mexico, Northwest Mexico (Sinaloa) N/A 0
Patricia October 4 – 15 Category 1 hurricane 90 (150) 964 None None 0
Depression October 14 – 15 Tropical depression 30 (45) 1004 None None 0
Rosalie October 20 – 24 Tropical storm 65 (100) 987 None None 0
Season Aggregates
25 cyclones May 28 – October 24   140 (220) 928 4 21 – 31

See also

Notes

  1. ↑ The peak intensity of Patricia is based off the values listed in the season's Monthly Weather Review.[1] According to the Hurricane Database, the storm attained peak winds of 90 mph (150 km/h) and a minimum pressure of 964 mbar (hPa; 28.47 inHg).[6]

References

  1. 1 2 3 4 5 6 7 8 9 Robert A. Baum (April 1975). "Eastern North Pacific Tropical Cyclones, 1974. Part 1" (PDF). Monthly Weather Review (American Meteorological Society) 103 (4). Bibcode:1975MWRv..103..301B. doi:10.1175/1520-0493(1975)103<0301:ENPTCP>2.0.CO;2. Retrieved October 19, 2011.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 Sharon Towry (June 1975). "Eastern North Pacific Tropical Cyclones, 1974. Part 2" (PDF). Monthly Weather Review (American Meteorological Society) 103 (6). Bibcode:1975MWRv..103..550T. doi:10.1175/1520-0493(1975)103<0550:ENPTCP>2.0.CO;2. Retrieved October 20, 2011.
  3. ↑ "Hurricane kills nine". Associated Press (The Windsor Star). June 18, 1974. p. 40. Retrieved October 20, 2011.
  4. ↑ "Ciclones Tropicales". Centro Nacional de Prevención de Desastres (in Spanish). Secretaría De Gobernación. 2011. Retrieved October 20, 2011.
  5. ↑ "Hurricane kills 22 in Acapulco". United Press International (The Vancouver Sun). June 19, 1974. p. 48. Retrieved October 20, 2011.
  6. 1 2 3 4 5 6 7 8 "Eastern North Pacific Hurricane Database: 1949-2010". Hurricane Research Division. National Oceanic and Atmospheric Administration. 2011. Retrieved December 6, 2011.
  7. 1 2 3 "The 1974 Central Pacific Tropical Cyclone Season". Central Pacific Hurricane Center. National Oceanic and Atmospheric Administration. March 4, 2007. Retrieved October 20, 2011.
  8. ↑ "1974 Missing (1974190N16242)". International Best Track Archive. 2011. Retrieved December 8, 2011.
  9. ↑ "1974 Missing (1974199N08262)". International Best Track Archive. 2011. Retrieved December 8, 2011.
  10. ↑ "1974 Missing (1974202N10263)". International Best Track Archive. 2011. Retrieved December 8, 2011.
  11. ↑ "1974 Missing (1974217N12226)". International Best Track Archive. 2011. Retrieved December 8, 2011.

External links

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