The 1964 Atlantic hurricane season featured the highest number of U.S.-landfalling hurricanes since 1933. The season officially began on June 15, and lasted until November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. The season was above average for the time, with thirteen named storms, seven hurricanes, and five major hurricanes. The first system, an unnamed tropical storm, developed on June 2, almost two weeks before the official start of the season. Striking Florida on June 6, the storm brought localized flooding to portions of Cuba and the Southeastern United States, leaving about $1 million in damage. The next storm, also unnamed, developed near the end of July; it did not impact land.
The effects of Hurricanes Cleo, Dora, and Isbell combined were devastating to Florida. Cleo also brought destruction to portions of the Caribbean, especially Guadeloupe and Haiti. After moving inland, Cleo brought flooding to states such as Virginia. Overall, the storm caused 220 deaths and about $198.5 million in damage. Dora lashed much of North Florida and southeastern Georgia with hurricane-force winds, leaving five fatalities and around $280 million in damage. In October, Isbell brought strong winds and several tornadoes to Florida, as well as flooding to Cuba and The Carolinas. Isbell killed seven people and left approximately $30 million in damage.
The strongest tropical cyclone of the season was Hurricane Cleo, a powerful Category 4 hurricane that severely affected areas in the Caribbean, including the Leeward Islands, Haiti, and Cuba. Cleo went on to hit the United States, in the eastern Florida peninsula as a minimal Category 2 hurricane, particularly in Miami, Florida, where the storm brought severe damage to the state alone, and bringing heavy rain, and severe flooding to the Carolinas in the United States East Coast as a tropical storm. The names Cleo, Dora, and Hilda were retired following the season. Collectively, the tropical cyclones resulted in 271 fatalities and approximately $640.63 million in damage.
Season summary
The Atlantic hurricane season officially began on June 15, 1964. It was a slightly above average season in which thirteen tropical storms formed, compared with the 1950–2000 average of 9.6 named storms. Seven of these reached hurricane status, which is slightly higher than the 1950–2000 average of 5.9. Five of the seven hurricanes reached major hurricane status – Category 3 or higher on the Saffir–Simpson scale – above the 1950–2000 mean of 2.3 per season. Prior to the season, National Hurricane Center director Gordon Dunn noted that the probability of a hurricane striking the United States was "astronomical." The tropical cyclones of the 1964 Atlantic hurricane season collectively caused at least 271 deaths and about $640.63 million in damage. The season officially ended on November 30, 1964.
The first system, an unnamed tropical storm, developed on June 2. It struck Florida as a tropical depression and then strengthened into a tropical storm while out at sea. The storm ceased to exist on June 11. Thereafter, the season went dormant for nearly seven weeks, as the next cyclone, another unnamed storm, did not form until July 23. This would be followed by the development of a third unnamed system on July 28. Tropical cyclogenesis increased in August, which had four tropical cyclones, Abby, Brenda, Cleo, and Dora. The strongest storm of the season, Cleo, peaked with maximum sustained winds of 150 mph (240 km/h) and a minimum barometric pressure of 938 mbar (27.7 inHg). Four additional storms originated in September, including Ethel, Florence, Gladys, and Hilda. Hurricane Isbell was the sole tropical cyclone to form in the month of October. The final system, another unnamed storm, existed developed on November 5 and dissipated on November 10.
The season's activity was reflected with an accumulated cyclone energy (ACE) rating of 153. ACE is, broadly speaking, a measure of the power of the hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, have high ACEs. It is only calculated for full advisories on tropical systems at or exceeding 39 mph (63 km/h), which is tropical storm strength.
Systems
Unnamed June tropical storm
A disturbance that moved out of the Intertropical Convergence Zone (ITCZ) developed into a tropical depression to the east of British Honduras (modern day Belize) on June 2. Moving slowly northward to north-northeastward across the Caribbean Sea and Gulf of Mexico, the depression failed to intensify significantly. Shortly after 12:00 UTC on June 6, it made landfall just south of Cedar Key, Florida, with winds of 30 mph (48 km/h). Early the following day, the depression emerged into the Atlantic Ocean near Jacksonville and began to strengthen and move northeastward. While located offshore South Carolina on June 7, the system became a tropical storm. Further deepening occurred slowly, with the storm peaking with winds of 70 mph (110 km/h) late on June 9. By June 11, it was absorbed by an extratropical low while located about 350 mi (560 km) south-southeast of Sable Island in Nova Scotia.
The storm brought local flooding to portions of western Cuba and the Southeastern United States. Some areas in North Florida experienced considerable damage from strong winds and hail associated with thunderstorm, particularly in Cross City. Damage in the Jacksonville area alone was over $300,000. A few gale warnings were issued between Myrtle Beach, South Carolina, and Nags Head, North Carolina. More than 8 in (200 mm) of rain in the former resulted in inundated streets and overflowing streams. Additionally, about 20 in (510 mm) of water covered streets in downtown Conway, South Carolina. Overall, the storm caused about $1 million in damage.
Unnamed July tropical storm
A low-pressure area formed near Columbia, South Carolina, early on July 23 and became a tropical depression. Due to its association with a mid to upper-level trough through July 25, the depression may have been a subtropical cyclone, though such a classification could not be confirmed prior to when satellite imagery became routine. The depression moved east-northeastward and emerged into the Atlantic near Kitty Hawk, North Carolina, early on July 24. Several hours later, the depression intensified into a tropical storm. Based on ship data and baroclinic intensification, the storm likely peaked with maximum sustained winds of 60 mph (97 km/h) just before becoming extratropical about 205 mi (330 km) of Nantucket, Massachusetts, around 12:00 UTC on July 26. The extratropical remnants moved northeastward towards Atlantic Canada, until another extratropical cyclone absorbed it near the south coast of Newfoundland late on July 27.
Unnamed July hurricane
Television Infrared Observation Satellite (TIROS) indicated an area of disturbed weather with a weak surface circulation in the vicinity of Cape Verde on July 25. Reports from a reconnaissance aircraft indicate that a tropical depression developed at 06:00 UTC on July 28, while located about halfway between the Leeward Islands and the northernmost islands of Cape Verde. Initially the depression moved rapidly west-northwestward, which likely caused the minimal intensification. By July 30, a north-northwest to south-southeast oriented trough forced the depression to re-curve north-northwestward.
While situated about 300 mi (485 km) east of Bermuda on July 31, it began heading northeastward. Later that day, the depression finally organized further and developed a well-defined rainband. The Atlantic hurricane database indicates that the depression strengthened into a tropical storm at 18:00 UTC on July 31, due to ships reports of winds reaching 46 mph (74 km/h). On August 1, it intensified further into a hurricane. Around that time, maximum sustained winds peaked at 85 mph (137 km/h). The storm continued moving rapidly northeastward and began to interact with a cold front. It transitioned into an extratropical cyclone on August 2, while located about 525 mi (845 km) east of Cape Race, Newfoundland.
Tropical Storm Abby
A weak trough developed into a tropical depression late on August 5 while located about 225 mi (360 km) south of Dauphin Island, Alabama. The depression moved westward and initially remained disorganized. At 12:00 UTC on August 7, the depression strengthened into Tropical Storm Abby. It was a small tropical cyclone, spanning a diameter of less than 100 mi (160 km). The storm quickly intensified further late on August 7. A few hours later, Abby made landfall near Matagorda, Texas, at just below hurricane intensity. Abby may have reached hurricane status, but the lack of definitive observations prevented an upgrade. It weakened to a tropical depression early on August 8, before dissipating later that day.
Overall, impact from this system was minor. In Texas, precipitation peaked at 6.14 in (156 mm) at the Victoria Regional Airport. However, only localized flooding occurred and rainfall was mostly beneficial. In the city of Victoria, several streets were temporarily inundated with water. A fishing company in Matagorda lost a portion of its roof. Abby resulted in an estimated $750,000 in losses, with $150,000 in damage to property and $600,000 to crops. The impacts from the storm were most severe in Jackson and Victoria counties, where damage to crops were estimated at $275,000 and $250,000, respectively.
Tropical Storm Brenda
A minor trough of low pressure was situated west of Bermuda in early August. An airline crew member observed a low-level circular cloud forming at 32.0°N, 69.0°W at 18:00 UTC on August 7. Early on August 8, a tropical depression developed about 135 mi (215 km) northwest of Bermuda. It moved east-southeastward and strengthened into Tropical Storm Brenda six hours later. At 13:00 UTC on August 8, the cyclone struck Bermuda with winds of 50 mph (80 km/h). The island experienced sustained winds up to 45 mph (72 km/h) and gusts up to 65 mph (105 km/h). A tornado damaged several aircraft, most of which were privately owned. Damage reached approximately $275,000.
Shortly after moving across Bermuda on August 8, spiral bands appeared on the island's radar. Advisories on Brenda were not initiated until 18:00 UTC on August 8, due to sparsity of data, making it difficult to confirm the existence of a tropical cyclone. A cold front caused the storm to re-curve northeastward on August 9. Brenda then began weakening and dissipated late on the following day, while located about 585 mi (940 km) east-northeast of Bermuda.
Hurricane Cleo
A tropical wave developed into Tropical Storm Cleo while located about 1,000 mi (1,610 km) east of Barbados late on August 20. It continued west-northwestward, quickly intensifying into a hurricane later on August 21. Cleo rapidly deepened and reached Category 3 early on August 22. Several hours later, Cleo struck Marie-Galante and the main island of Guadeloupe with winds of 125 mph (201 km/h). The storm then intensified into a Category 4 hurricane and entered the Caribbean Sea. While located south of the Dominican Republic around 18:00 UTC on August 23, Cleo attained its peak intensity with winds of 155 mph (249 km/h). The hurricane then made landfall near Les Cayes, Haiti, on August 25 at the same intensity. The storm re-emerged into the Caribbean hours later as a Category 2 hurricane but weakened to Category 1 intensity around 12:00 UTC. Cleo briefly moved ashore near Cape Cruz, Cuba, with winds of 80 mph (130 km/h).
The cyclone emerged into the Gulf of Guacanayabo, before striking Sancti Spíritus Province as a minimal hurricane early on August 26. Cleo briefly weakened to a tropical storm before emerging into the Atlantic and re-strengthening, becoming a hurricane again at 18:00 UTC. Now moving north-northwestward, the system reached Category 2 intensity early on August 27, hours before striking Miami Beach, Florida, with winds of 110 mph (180 km/h). The system quickly weakened inland, falling to tropical storm intensity near Port St. Lucie later that day. Cleo briefly re-emerged into the Atlantic off the coast of North Florida, before making another landfall on St. Simons Island, Georgia, early on August 29 with winds of 60 mph (97 km/h). Cleo weakened to a tropical depression over South Carolina on August 30 but did not dissipate. Thereafter, the cyclone curved northeastward and eventually eastward while crossing the Carolinas and Virginia. Cleo re-intensified into a tropical storm while re-entering the Atlantic near Norfolk, Virginia, on September 1. It moved east-northeastward and became a hurricane again about 24 hours later. Late on September 3, Cleo became a Category 2 hurricane again. The cyclone then to the northeast and lost tropical characteristics, becoming extratropical to the southeast of Newfoundland on September 4. The remnants meandered in the Atlantic until dissipating about halfway between southern Greenland and Ireland on September 10.