The 1971 Atlantic hurricane season was an active Atlantic hurricane season overall, producing 14 named storms (including two nameable systems that went unnamed), of which 6 strengthened into hurricanes, and 2 further strengthened into major hurricanes. The season officially began on June 1, 1971, and lasted until November 30, 1971. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. This season, the first storm, Arlene, developed on July 4, while the last, Laura, dissipated on November 22.
Activity was steady through most of the season. Hurricane Edith was its strongest system, becoming a strong Category 4 on the Saffir–Simpson scale. It struck Nicaragua at peak intensity, killing dozens, and later hit southern Louisiana. Hurricane Ginger, the second of the season's two major hurricanes, was its longest-lived system, lasting 27 days from early September to early October, setting a record for the longest known duration of a North Atlantic tropical cyclone (not surpassed until 2003). Ginger moved ashore in North Carolina, producing heavy rains and damaging winds. An unnamed storm in August attained hurricane status further north than any other Atlantic hurricane on record. On September 11–13, there were five active Atlantic tropical cyclones at one time. Despite the activity, damage in the United States totaled about $235 million (1971 USD, USD), which National Hurricane Center forecaster Paul Hebert noted was "pretty small considering we had five storms in a row strike the U.S." Most of the damage came from Tropical Storm Doria, which affected much of the East Coast of the United States. Hurricane Fern struck Texas after executing an unusual track, dropping heavy rainfall and producing flooding.
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Systems
Tropical Storm Arlene
The origins of Arlene were from a cold front that exited the East Coast of the United States on July 2 and stalled offshore. A frontal wave developed the next day, steadily developing due to thermal instability. On July 4, the system organized into Tropical Storm Arlene about southeast of Cape Fear, North Carolina. While in its formative stages, it dropped rainfall along the coast of the Carolinas, peaking at in Pinopolis, South Carolina. Arlene tracked northeastward due to a ridge over New England, and the cyclone passed just southeast of the Outer Banks. In the post-season summary, meteorologist Neil Frank noted, "the surprising element in the development of Arlene was the rapidity of the transformation process."
Arlene continued northeastward, possessing a circular mass of convection with spiral rainbands. Late on July 6, the storm attained peak winds of 60 mph (95 km/h), based on a ship report. It weakened thereafter, and Arlene transitioned into an extratropical cyclone early on July 7 just south of Sable Island. The storm capsized a boat in the Grand Banks of Newfoundland, and the crew of 12 was rescued.
Unnamed hurricane
A hybrid-type depression formed east of Bermuda on July 29. It moved rapidly southwestward before turning to a northwest drift. On August 3, it was classified as a tropical depression, and the next day the system passed near Bermuda. The depression accelerated to the northeast, strengthening into a tropical storm on August 5. It intensified further due to baroclinity, or enhanced instability through different levels of the atmosphere caused by temperature and moisture gradients. On August 6, a drilling rig about southeast of Newfoundland recorded sustained winds of with gusts to 126 mph (204 km/h) at an altitude of ; this suggested the storm attained hurricane status at 44°North, which is the northernmost location for a tropical storm to intensify into a hurricane.
Despite the intensity, the cyclone was not purely tropical; although the radius of maximum winds was only , the thermal structure did not resemble a tropical cyclone, and there was no precipitation or convection near the center. It continued northeastward as a strong extratropical cyclone and meandered across the far northern Atlantic. It was not named operationally, but it was later added to the Atlantic hurricane database.
Hurricane Beth
On August 9, an upper-level low developed off the coast of Florida, and the next day spawned a tropical depression near Grand Bahama. After briefly moving southeastward across the island, the newly developed cyclone tracked slowly northeastward, eventually encountering conditions favorable for development. Late on August 13, the depression intensified into Tropical Storm Beth off the coast of North Carolina, and it quickly strengthened into a hurricane by August 15. After reaching peak winds of off the coast of Cape Cod, Beth slightly weakened and later moved ashore near Copper Lake, Nova Scotia as a strong tropical storm. Shortly thereafter, Beth was swept up by a nearby cold front and transitioned into an extratropical cyclone.
The hurricane left extensive damage in its wake, especially to crops and infrastructure. Halifax International Airport reported 10.49 in (266 mm) of rainfall in a 30‑hour span, which caused widespread flooding. Several bridges in the region were washed out, while railways were covered by water, forcing trains to suspend their operation. Overall monetary damage from Beth is estimated up to $5.1 million (1971 USD, USD). One person was indirectly killed by the hurricane in a traffic accident induced by heavy rainfall.
Tropical Storm Seven
On August 12, a tropical depression developed off the coast of Florida. It quickly moved ashore after strengthening to a tropical storm, reaching Lake Okeechobee before looping to the northwest. While moving across the state, it dropped heavy rainfall of around along the west coast. In Pinellas Park, the heavy rains led to flash flooding that forced 200 families from their house, including one that required evacuation from a helicopter. Damage in the region was estimated at $250,000 (1971 USD, USD).
The depression emerged into the Gulf of Mexico on August 15 near Tampa, and later turned to the northeast ahead of an upper-level low. The depression remained weak as it meandered off the Southeast coast and dissipating on August 17 near the Delmarva Peninsula. In South Carolina, it produced its heaviest rainfall, totaling in Sullivan's Island. In nearby Savannah, Georgia, the rainfall forced about 100 families from their houses in low-lying areas. The remnants continued northeastward through the Mid-Atlantic States and New England, crossing into Canada on August 20.
Tropical Storm Chloe
A tropical wave moved off the coast of Africa on August 13, moving westward for several days before organizing into a tropical depression on August 18 about east of Barbados. It quickly moved through the Lesser Antilles, where it produced wind gusts up to . The cyclone also dropped heavy rainfall up to on Barbados and Martinique. After entering the eastern Caribbean Sea, the depression intensified into Tropical Storm Chloe on August 20. About 18 hours after attaining tropical storm status, Chloe quickly strengthened to peak winds of about 215 mi (345 km) south of the Mona Passage, as reported by reconnaissance aircraft.
After reaching peak intensity, Chloe began weakening as it turned to the west-southwest, and late on August 22, it was downgraded to a tropical depression as a weakening ridge to its north cut off the low-level inflow. For several days it continued generally westward, gradually losing organization. While passing south of Jamaica, the storm prompted the evacuation of the SS Hope, a hospital ship, at Kingston. Late on August 24, Chloe dissipated about east of San Pedro Town, Belize. The remnants of Chloe later spawned Hurricane Lily in the eastern Pacific Ocean.
Tropical Storm Doria
Tropical Storm Doria, the costliest storm of the season, developed from a tropical wave on August 23 to the east of the Lesser Antilles, and after about three days without development attained tropical storm status to the east of the Abaco Islands in the Bahamas. Doria turned to the north, and reached peak winds of 70 mph (110 km/h) as it was making landfall near Morehead City, North Carolina. It turned to the northeast hugging the coast and holding its intensity as it passed the North Carolina and Virginia coasts (although it may have briefly become a hurricane - the data was inconclusive), and moved through the Mid-Atlantic and New England as a tropical storm before becoming an extratropical storm over Maine on August 28.
In North Carolina, Doria produced moderate rainfall, resulting in localized flooding and damage. The storm spawned a tornado near Norfolk, Virginia, damaging twelve houses and downing hundreds of trees. Tropical Storm Doria dropped heavy precipitation in New Jersey, peaking at 10.29 in (261 mm) in Little Falls. The rainfall led to record-breaking river levels and flooding in several houses, resulting in damage to dozens of houses across the state. Moderate damage and rainfall continued along its path into New England and southeastern Canada. In all, Tropical Storm Doria caused seven deaths and $147.6 million (1971 USD, USD).
Hurricane Fern
Hurricane Fern was the first of four tropical systems to develop in association with an extended surface trough across the Gulf of Mexico into the open Atlantic, along with Ginger, Heidi, and a strong tropical depression. Fern developed on September 3 in the central Gulf of Mexico. It moved very close to southern Louisiana the next day, but due to increased ridging to the north the depression moved southwestward and remained over water. On September 7, the depression intensified into Tropical Storm Fern. Fern later turned to the northwest, intensifying into a hurricane on September 10. It quickly reached peak winds of , moving ashore early on September 11 between Freeport and Matagorda, Texas as a tropical storm. Fern dissipated on September 13 over northeastern Mexico.
The precursor of Fern dropped rainfall up to of rainfall across South Florida, while totals of up to were reported in southeastern Louisiana where it made its first landfall. As it struck Texas, Fern produced strong winds up to , along with storm tides and heavy rainfall; the highest precipitation total was in Beeville. The heavy rainfall caused severe flash flooding that isolated numerous small towns in the southeastern portion of the state, damaging 7,500 buildings. In all, Fern left two indirect deaths and moderate damage totaling $30.2 million (1971 USD, USD).
Hurricane Edith
Hurricane Edith, the strongest storm of the season, developed from a tropical wave on September 5 to the east of the southern Lesser Antilles. It moved quickly across the southern Caribbean Sea, intensifying into a hurricane just off the north coast of South America. Edith rapidly intensified on September 9 and made landfall on Cape Gracias a Dios as a strong Category 4 hurricane on the Saffir-Simpson Hurricane Scale. It quickly lost intensity over Central America and after briefly entering the Gulf of Honduras it crossed the Yucatán Peninsula in Mexico. After moving across the Gulf of Mexico, a trough turned the storm to the northeast and Edith, after having restrengthened while accelerating towards the coast, made landfall on Louisiana with winds of 90 mph (150 km/h) on September 16. Edith steadily weakened over land and dissipated over Georgia on September 18.