1974 Pacific hurricane season
The 1974 Pacific hurricane season featured one of the most active periods of tropical cyclones on record with five storms existing simultaneously. 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
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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.
Systems
Tropical Storm Aletta
A tropical disturbance formed to the south of the Gulf of Tehuantepec on May 24; sea surface temperatures in the area were around. The disturbance slowly organized over the next 60 hours, as it was detaching from the Intertropical Convergence Zone. 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
Blanca formed officially on June 5 and dissipated on June 8 due to surface temps being colder than the required 80 °F for tropical activity. Blanca never had a chance to impact land and had it did at its peak intensity, it would have never done much as its peak wind speeds were 60 mph. Blanca also was the 2nd named storm of the season starting the hurricane season off very weakly. The brunt of the season would start 2 months later in late August.Hurricane Connie
Hurricane Connie was the first major hurricane. It took a bizarre, twisting path but never made landfall. Connie was never expected to make landfall because of where it formed and the path it took. Connie's track was unique with 2 major turns and potentially 1 loop.Hurricane Dolores
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, the storm made landfall near Acapulco. Once onshore, Dolores rapidly dissipated and was last noted on June 17.Across Southwestern Mexico, Hurricane Dolores produced heavy rains that triggered widespread flooding and mudslides. Numerous roads sustained damage, separating communities from surrounding areas. At least 18 people were killed and 32 others were injured by the storm. Additionally, an estimated 173,000 people were affected across the country.
Tropical Storm Eileen
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. Tracking northward, the system gradually attained tropical storm intensity. Due to the lack of direct observations, Eileen's intensity was based solely off satellite estimates; these estimates indicated the cyclone to have attained peak winds of 40 mph and a minimum pressure of 997 mbar. 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. The remnants of Eileen were last noted on July 4 well to the southwest of the southern tip of Baja California.Hurricane Francesca
Francesca was a category 1 hurricane. It neared Baja California by the 17th but turned away before striking.Hurricane Gretchen
Gretchen was a category 2 hurricane that threatened southern Baja California, but it turned away without affecting land.Tropical Storm Helga
Helga was a storm that did not affect land.Hurricane Ione
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.Intensification slowed on August 24 as Ione attained winds in excess of 100 mph. Over the next day, the system turned northward and attained its peak intensity late on August 25 with winds of 115 mph. Additionally, the storm attained an estimated minimum central pressure of 954 mbar. 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.
Tropical Storm Olive
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 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 southeast of Johnston Island.Hurricane Joyce
Joyce was a weak hurricane that did not affect land.Hurricane Kirsten
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 Lorraine took an erratic, Z-shaped path during its life. It formed on August 23 and dissipated August 28.Hurricane Maggie
Hurricane Maggie was the strongest storm of the season. It reached Category 4 but never threatened land.Hurricane Norma
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. On September 10, Norma briefly strengthened into a hurricane, with peak winds estimated at 75 mph before making landfall west of Acapulco. Within hours of moving onshore, the storm rapidly deteriorated and dissipated later that day.Heavy rains produced by Norma triggered mudslides in and around Acapulco, resulting in three fatalities.
Hurricane Orlene
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
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, at which time Patricia attained its peak intensity with winds estimated at 90 mph. 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. The remnants of the storm were last noted on October 17 well to the east-southeast of Hawaii.Tropical Storm Rosalie
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. Tracking generally towards the west-southwest, Rosalie attained its peak intensity with winds estimated around 65 mph on October 21. Later that day, the system neared an area of more stable air. Gradual weakening ensued over the following days, with Rosalie degrading to tropical depression status on October 23. Void of convection, the remnant swirl of Rosalie was last noted on October 24 well to the southeast of Hawaii.Other systems
In addition to the eighteen named storms, there were seven tropical depression during the course of the season.- July 9 – 13, 35 mph
- July 18 – 20, 35 mph
- July 21 – 26, 35 mph
- July 31 – August 11, 35 mph 1001 mbar
- August 5 – 7, 35 mph
- September 3 – 7, 35 mph 1001 mbar
- October 14 – 15, 30 mph 1004 mbar
Storm names
In this season, the Central Pacific named storms from the western Pacific's typhoon list. One name, Olive, was used.