The 1965 Atlantic hurricane season was the first to use the modern-day bounds for an Atlantic hurricane season, which are June 1 to November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. It was a slightly below average season, with 10 tropical cyclones developing and reaching tropical storm intensity. Four of the storms strengthened into hurricanes. One system reached major hurricane intensity – Category 3 or higher on the Saffir–Simpson hurricane scale. The first system, an unnamed tropical storm, developed during the month of June in the southern Gulf of Mexico. The storm moved northward across Central America, but caused no known impact in the region. It struck the Florida Panhandle and caused minor impact across much of the Southern United States. Tropical cyclogenesis halted for over two months, until Anna formed on August 21. The storm remained well away from land in the far North Atlantic Ocean and caused no impact.
Hurricane Betsy was the strongest and most devastating storm of the season. Extensive damage from Betsy was reported in the Bahamas, Florida, and Louisiana, particularly the New Orleans area. It was the first hurricane in the history of the United States to result in at least $1 billion (1965 USD) in losses. Hurricane Carol meandered in the eastern Atlantic for over two weeks from mid-September to very early October. Impact on land from Carol was minimal. In late September, Tropical Storm Debbie developed in the northwestern Caribbean and moved slowly across the region, before later reaching the Gulf of Mexico. The storm dissipated just offshore of Louisiana, which resulted in only minor impact along the Gulf Coast of the United States. The final tropical cyclone, Hurricane Elena, formed on October 12. Elena remained at sea for nearly a week and caused no damage on land. Collectively, the storms of the 1965 Atlantic hurricane season caused 76 fatalities and $1.68 billion in damage, almost entirely due to Hurricane Betsy.
Season summary
This was the first Atlantic hurricane season to start on June 1 and end on November 30, which is the modern-day season bounds. A total of 13 tropical depressions formed. Ten of those tropical depression intensified into a tropical storm, which was just slightly below the National Oceanic and Atmospheric Administration's 1950–2005 average of 11. Four of those tropical storms attained hurricane status, slightly below the average of six. One hurricane intensified into a major hurricane, which is Category 3 or greater on the Saffir–Simpson scale. This was slightly below the average of two per season. Overall, the tropical cyclones of this season collectively caused about $1.68 billion in damage and 76 deaths.Season activity began with the formation of an unnamed tropical storm over the southern Gulf of Mexico on June 13. There were no other tropical storms in the Atlantic basin until the latter part of August, when hurricanes Anna and Betsy formed. The latter developed on August 27 and eventually became the most intense tropical cyclone of the 1965 season, peaking as a Category 4 hurricane with maximum sustained winds of on September 2. While Betsy would mostly exist in September, the month also featured four additional tropical cyclones – an unnamed tropical storm, Hurricane Carol, a tropical depression, and then Debbie. In October, three tropical systems formed, including two unnamed tropical storms and Hurricane Elena. The final tropical cyclone of the 1965 season, an unnamed tropical storm, developed from a previously non-tropical cyclone northeast of the Lesser Antilles on November 29. The storm persisted into the month of December, before dissipating on December 2.
The season's activity was reflected with an accumulated cyclone energy (ACE) rating of 88, which was near the 1950–2005 average of 93.2. 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 cyclones with winds exceeding , which is tropical storm strength.
Systems
June tropical storm
A cut-off low-pressure area developed from a shear trough in the northwestern Gulf of Mexico on June 9. The low caused the detachment of a disturbance from the Intertropical Convergence Zone, which was located near the south coast of Guatemala. After moving across Guatemala and Mexico, the low emerged into the Gulf of Mexico on June 13. The low intensified on the following day, reaching tropical storm status at 0600 UTC. It likely was a subtropical storm, however, the lack of consistent satellite data precludes such a classification. Operationally, the system was considered a tropical depression for its entire duration, thus, this went unnamed. The storm began curving northeastward, and by early on June 15, it peaked with winds of .
At 1100 UTC on June 15, the storm made landfall near Santa Rosa Beach, Florida, at the same intensity. Inland, the storm continued northeastward and became extratropical over South Carolina at 0000 UTC on June 16. Tides along the coast of the Florida Panhandle were above normal. The storm brought sustained winds of 50 to 60 mph (85 to 105 km/h) with gusts up to at Alligator Point. Winds blew the roof off of two beach cottages on St. George Island, while tides sank or washed ashore several small boats. The storm also produced rainfall up to in Wewahitchka. Slick roads in Tallahassee resulted in several car accidents, but no injuries occurred. The rains also left street flooding in the Inglewood neighborhood of Tallahassee, forcing the evacuation of two families. Two tornadoes were spawned in Florida, with one damaging houses and a mobile home in Live Oak. The storm also brought rainfall to several other states.
Hurricane Anna
A weak circulation was noted by Television Infrared Observation Satellite (TIROS) near Cape Verde on August 16. During the next five days, the system tracked west-northwestward or northwestward, while conditions gradually became favorable for tropical cyclogenesis. At 0600 UTC on August 21, it is estimated that the system became Tropical Storm Anna. While Anna was tracking north-northeastward on August 23, an eye feature appeared on TIROS. After another aircraft reported an eye on its radar, Anna was upgraded to a hurricane later that day. Early on August 24, Anna reached maximum sustained winds of while accelerating northeastward. Anna began losing tropical characteristics, and early on the following day, it transitioned into an extratropical storm while about halfway between the Azores and Greenland.
Hurricane Betsy
A tropical disturbance developed into a tropical depression on August 27, while well east of the Windward Islands. It tracked generally west-northward until crossing the Leeward Islands on August 28. Early the next day, the depression intensified into Tropical Storm Betsy, shortly before striking Saint Martin and Anguilla. Betsy continued to intensify after re-emerging into the western Atlantic, becoming a hurricane on September 1. After executing a brief cyclonic loop, the storm then turned to the west. Later on September 1 and into September 2, Betsy rapidly intensified and peaked as a Category 4 hurricane with winds of on September 2. However, the storm fell back to Category 3 intensity early the next day. By September 5, Betsy executed another cyclonic loop northeast of the Bahamas and fell to as low as Category 1 intensity around 0000 UTC on September 6. The storm fluctuated between Category 2 and 3 as it headed southwestward and then westward over the next day, passing over or close to several Bahamian islands, including Great Abaco and Andros. The storm produced very strong winds and rough seas in the Bahamas, with a peak wind gust of at Hope Town. Betsy caused one fatality and approximately $14 million in damage in the island chain, mostly to agriculture and crops.
By early on September 8, Betsy made landfall near Tavernier, Florida, as a Category 3 hurricane. In South Florida, the storm brought strong winds and significant storm surge. Water reached several feet in height in upper Florida Keys, inundating highways and the first floor of buildings. Nearly all of the land south of Homestead Air Force Base and east of U.S. Route 1 was covered by water. There were 8 deaths and $120 million in losses, which included both property and agriculture. Betsy entered into the Gulf of Mexico later on September 8 and re-strengthened into a Category 4 hurricane on September 10, reaching a secondary peak with winds of . However, further intensification was halted after Betsy made landfall in Grand Isle, Louisiana, around 0400 UTC. In Louisiana, strong winds and rough seas caused extensive damage. Storm surge inundated the levees in New Orleans, flooding much of the city. Throughout the state, more than 22,000 homes were either damaged or destroyed, and 168,000 people were left without electricity. The storm caused more than 17,000 injuries and resulted in 58 deaths. Damage in the state of Louisiana reached $1.2 billion. Once inland, the storm turned northeastward and rapidly weakened, becoming extratropical over Tennessee on September 11. Impact in other states ranged from minor to moderate. Overall, Betsy caused about $1.43 billion in damage and 76 fatalities. Betsy was the first hurricane in the United States to cause at least $1 billion in damage.
Early September tropical storm
A cold front moved eastward from North America into the western Atlantic Ocean on August 28. An extratropical low developed on August 31 over the north Atlantic, which degenerated into a trough three days later. On September 4, another extratropical storm developed, located about 800 mi (1,285 km) south of Newfoundland. The system attained gale-force winds a day later, and turned westward on September 6, steered by a building ridge to the north. On September 7, the storm transitioned into a tropical storm, after its wind field became more symmetrical. Later that day, the storm attain winds of , recorded by nearby ships. The storm turned to the east and northeast, crossing over its former path. On September 10, the tropical storm again transitioned into an extratropical storm, which later passed southeast of Newfoundland. The storm moved across the northern Atlantic Ocean, dissipating on September 13 southwest of Ireland.
Hurricane Carol
A tropical wave emerged into the Atlantic from the west coast of Africa on September 15, and developed into a tropical depression by early on the following day. It headed steadily westward and strengthened into Tropical Storm Carol late on September 17. The storm began curving northwestward by the following day. Operationally, advisories were not initiated until 1900 UTC on September 19, after winds had already reached . Carol then slowed and began turning north-northward. Later on September 20, a Navy reconnaissance flight confirmed a circulation and also measured hurricane-force winds. Thus, Carol was upgraded to a hurricane at 1800 UTC on September 20.