1972 Atlantic hurricane season

The 1972 Atlantic hurricane season was a significantly below average season, having only seven named storms, four fully tropical storms (the fewest since 1930) and three subtropical storms. It officially began on June 1, 1972, and lasted until November 30, 1972. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. The first storm, Subtropical Storm Alpha, developed on May 23 off the Southeast United States and struck Florida, causing minor damage and two fatalities.

The most significant storm of the season was Hurricane Agnes, which at the time was the costliest United States hurricane, until Frederic in 1979. After brushing the western tip of Cuba, the hurricane made landfall on the Florida Panhandle. It caused at least $2.1 billion (1972 USD) in damage and 137 fatalities, mostly from inland flooding in Pennsylvania and New York. The strongest hurricane of the season was Betty, which reached peak winds of 105 mph while west of the Azores. Tropical Storm Carrie passed just offshore of Massachusetts, causing heavy rainfall and resulting in four fatalities, but leaving only $1.78 million in damage. The remaining tropical systems caused no significant effects on land.

Due to a strong El Niño only three systems strengthened into hurricanes, none of which intensified into major hurricanes. Only four other seasons since the start of the satellite era—1968, the 1986, 1994, and 2013—did not have a major hurricane. In addition, the season was the first to name subtropical storms, using the Phonetic Alphabet. Collectively, the storms of the 1972 Atlantic hurricane season resulted in 137 deaths and over $2.1 billion in damage.

Season summary
The Atlantic hurricane season officially began on June 1, 1972. Although 19 tropical cyclones developed, only seven of were named, below the 1950-2000 average of 9.6 named storms per season. Of the seven tropical or subtropical storms, three of them strengthened into hurricanes, which is also below average. None of the three hurricanes became major hurricanes, which is Category 3 or greater on the Saffir–Simpson hurricane wind scale. Overall, the season was inactive, despite having a similar number of tropical waves as the previous season. The lack of activity was attributed to an El Niño – which causes below normal sea surface temperatures over the eastern Atlantic – and strong vertical wind shear. One subtropical storm and two hurricanes made landfall during the season and caused at least 137 fatalities and more than $2.1 billion in damage. The last storm of the season, Subtropical Storm Delta, became extratropical on November 7, about 23 days before the official end of hurricane season on November 30.

Tropical cyclogenesis first occurred in the month of May, with the development of Subtropical Storm Alpha. The month of June featured three tropical cyclones, including Hurricane Agnes and two tropical depressions. Three more systems formed in July, though all of them failed to reach tropical storm status. August was the most active month of the season, with five systems, including Hurricane Betty, Tropical Storm Carrie, and three tropical depressions. September featured slightly less cyclogenesis, with Hurricane Dawn, Subtropical Storm Charlie, and two tropical depressions. An additional three tropical depressions formed in October. Subtropical Storm Delta was the sole system in November, lasting from November 1 to November 7.

The season's activity was reflected with an Accumulated Cyclone Energy (ACE) rating of 36, the lowest value since 1962. Broadly speaking, ACE is a measure of the power of a tropical or subtropical storm multiplied by the length of time it existed. Therefore, a storm with a longer duration, such as Betty, will have high values of ACE. It is only calculated for full advisories on specific tropical and subtropical systems reaching or exceeding wind speeds of 39 mph. Accordingly, tropical depressions are not included here. After the storm has dissipated, typically after the end of the season, the NHC reexamines the data, and produces a final report on each storm. These revisions can lead to a revised ACE total either upward or downward compared to the operational value.

Subtropical Storm Alpha
A subtropical depression developed from a cold-core low pressure area southeast of the Carolinas on May 23. After initially moving northeastward, it turned sharply southward on May 26 due to a building ridge of high pressure. Later that day, the system strengthened into Subtropical Storm Alpha and proceeded to move toward the coast of Georgia. After peaking with maximum sustained winds of 70 mi/h, Alpha began weakening. Late on May 27, the storm made landfall near Brunswick, Georgia, with winds of 45 mph. Alpha weakened to a subtropical depression and dissipated after entering the northeastern Gulf of Mexico on May 29.

Rough seas generated by the storm resulted in two people drowning in Florida and halted work to deepen a harbor at the Mayport Naval Station in Jacksonville. Tides along the Georgia coast reached 2 to 3 ft above normal, which caused some flooding and beach erosion. Wind gusts reached 58 mph on Saint Simons Island. The winds knocked down trees and power lines, leaving some people without power in eastern Georgia. Damage was minor but widespread in the state, estimated at over $50,000. Moderate rains spread in coastal areas from South Carolina through southern Florida. North Carolina also experienced about $50,000 in damage, mostly due to erosion. Alpha was the first named subtropical storm.

Hurricane Agnes
A polar front and an upper trough over the Yucatán Peninsula spawned a tropical depression on June 14. The storm emerged into the western Caribbean Sea on June 15, and by the following day, it strengthened into Tropical Storm Agnes. The storm curved northward and brushed western Cuba on June 17. Agnes continued to intensify, and on June 18, it was upgraded to a hurricane. Minimal fluctuations in intensity occurred before the storm made landfall near Panama City, Florida, on June 19. After moving inland, Agnes rapidly weakened and was only a tropical depression when it entered Georgia. Thereafter, weakening slowed as the storm crossed over Georgia and into South Carolina. However, while over eastern North Carolina on June 21, Agnes re-strengthened into a tropical storm, as a result of baroclinic activity. Early the following day, the storm emerged into the Atlantic Ocean before re-curving northwestward and making landfall near New York City as a strong tropical storm. Agnes quickly merged with a non-tropical low pressure system on June 23.

Heavy rainfall occurred in western Cuba, causing flooding that destroyed 97 houses, isolated a few cities, and flatted crops in low-lying areas. The storm left seven fatalities. Agnes caused a significant tornado outbreak, with at least 26 confirmed twisters, 24 of them in Florida and the other two in Georgia. The tornadoes alone resulted in over $4.5 million in damage and six fatalities. At least 2,082 structures in Florida suffered either major damage or were destroyed. About 1,355 other dwellings experienced minor losses. Though Agnes made landfall as a hurricane, no hurricane-force winds were reported. Abnormally high tides resulted in extensive damage, especially between Apalachicola and Cedar Key. The storm left nine deaths and approximately $40 million in damage in Florida. Generally minor effects were also recorded in the states of Alabama, Delaware, Georgia, Ohio, South Carolina, and Tennessee, as well as the New England region. However, one fatality was reported in Delaware and three were recorded in Georgia.

The most significant effects, by far, occurred in Pennsylvania, mostly due to severe flooding. Precipitation peaked at 18 in in Schuylkill County, causing several creeks and rivers crest at record height, including the Delaware, Juniata, Lackawanna, Susquehanna, and West Branch Susquehanna rivers. More than 100,000 people were forced to leave their homes due to flooding. In the state of Pennsylvania, more than 3,000 businesses and 68,000 homes were destroyed, leaving at least 220,000 people homeless. Agnes remains one of the worst natural disasters in Pennsylvania. New York also suffered severe damage. Similarly, rivers in the state crested high, including the Allegheny, Chemung, Genesee, Susquehanna, and Tioga rivers. Corning, Elmira, and Olean, as well as many other Southern Tier towns, were severely flooded. Throughout New York, 32,832 homes were damaged and 628 others were damaged. A total of 1,547 small businesses were extensively damaged or demolished. In Canada, a mobile home was toppled, killing two people. Overall, Agnes caused 131 fatalities and over $2.1 billion in damage.

Hurricane Betty (Bravo)
An area of disturbed weather appeared on satellite imagery while forming within an old frontal zone on August 21. At 1200 UTC on the following day, a subtropical depression developed about 290 mi north-northeast of Bermuda. The system strengthened slowly as it headed east-northeastward or eastward and by August 24, it became Subtropical Storm Bravo. During the next 24 hours, minimal intensification occurred. However, a deepening high-level trough and a building ridge enhanced outflow and deep convection on August 25. Additionally, reconnaissance aircraft flights began indicating a transition to a warm-core. Unfavorable northwesterly winds briefly halted further development, though by late on August 26, Bravo resumed acquiring tropical characteristics after another deepening trough accelerated the storm eastward.

After reconnaissance aircraft reported winds of 98 mph and satellite imagery indicated a storm with a classic cyclonic appearance, Bravo was reclassified as Hurricane Betty while located about 920 mi west of the Azores on August 27. After some further strengthening, Betty attained its peak intensity as a Category 2 hurricane with maximum sustained winds of 105 mph and a minimum barometric pressure of 976 mbar early on August 28. The hurricane then moved rapidly east-northeastward before decelerating late on the following day. Around that time, northerly winds aloft caused Betty to weaken to a Category 1 hurricane. After briefly moving southward, the storm curved back to a general westward direction and fell to tropical storm intensity on August 31. Later that day, Betty turned northward ahead of a trough and became extratropical about 565 mi northwest of Corvo Island in the Azores on September 1.

Tropical Storm Carrie
A complex system combining a tropical wave and an upper-level low led to the formation of a tropical depression east of Florida on August 29. It managed to become a tropical storm on August 31 and reached initial peak winds of 60 mph later that day. However, upper-level winds increased, causing Carrie to weaken to a minimal tropical storm by September 2. Due to baroclinic processes, Carrie began to re-intensify. As a result, Carrie attained its peak winds of 70 mph just prior to transitioning into an extratropical cyclone on September 3. The extratropical cyclone continued northeastward, and struck eastern Maine on September 4. By the following day, the extratropical cyclone dissipated over the Gulf of Saint Lawrence.

Carrie had a minimal impact on the East Coast south of New England, limited to increased swells, gusty winds, and light rainfall. The worst conditions occurred over southeastern New England, where wind gusts reached 84 mph and rainfall exceeded 1 ft. Damage was most severe along and slightly inland from the coast. Thousands of people became stranded on offshore islands of Massachusetts after dangerous conditions created by the storm prompted the suspension of steamship service. Overall, damage was generally light, with total monetary losses valued at $1.78 million. Four deaths were blamed on the storm.

Hurricane Dawn
A tropical wave, combined with an upper tropospheric trough, resulted in the development of a tropical depression near Cay Sal Bank, Bahamas, on September 5. Later that day, the depression struck Key Largo, Florida, before moving inland over the mainland of Florida. The storm brought very light rainfall to the state, peaking at 1.19 in in Tavernier. The system moved northeastward and soon re-emerged into the Atlantic. While located north of Grand Bahama on September 6, the depression intensified into Tropical Storm Dawn. On September 7, a cold low pressure developed near Cape Hatteras, North Carolina, which would influence much of Dawn's movement. Around that time, the storm strengthened into a Category 1 hurricane. Dawn then curved west-northwestward on September 8 and peaked with maximum sustained winds of 80 mph and a minimum barometric pressure of 997 mbar.

With Dawn appearing as a threat to the Mid-Atlantic, storm and gale warnings were issued from Chincoteague Inlet, Virginia, to Cape May, New Jersey, on September 8. However, the hurricane veered southeastward on September 9 and weakened to a tropical storm. By late on September 10, after the cold low pressure area relinquished influence over Dawn, the cyclone began moving westward, but continued to deteriorate. Dawn weakened to a tropical depression while well east of Georgia late on September 12. The system approached the Sea Islands on September 13, but curved northeastward and remained offshore. Dawn dissipated less than 15 mi east of Isle of Palms, South Carolina, on September 14. The storm also produced very light rainfall in Georgia and South Carolina.

Subtropical Storm Charlie
A very small, circular subtropical depression developed about 460 mi northeast of Bermuda on September 19. Initially, the storm moved north-northeastward and strengthened into Subtropical Storm Charlie early the following day. It then moved quickly northeastward and continued to strengthen. Later on September 20, Charlie peaked with maximum sustained winds of 65 mph. The system soon lost tropical characteristics and transitioned into an extratropical cyclone about 630 mi east of Cape Race, Newfoundland, early on September 21. However, the extratropical storm deepened significantly, reaching a barometric pressure of 944 mbar, a reading typical of a strong Category 3 hurricane. Early on September 22, the extratropical cyclone dissipated over the far north Atlantic.

Subtropical Storm Delta
A southwestward-moving cold-core low pressure area developed into a subtropical depression while located about 950 mi west-southwest of Flores Island in the Azores on November 1. After forming, the system soon strengthened and was upgraded to Subtropical Storm Delta. Early on November 3, Delta attained its peak intensity with maximum sustained winds of 45 mph and a minimum barometric pressure of 1001 mbar. Around that time, the subtropical storm briefly moved southward, before beginning a general eastward movement on November 4. Delta soon began to weaken and was reduced to a subtropical depression by the following day. It continued eastward until November 6, at which time the storm decelerated and curved northward. Delta dissipated while located about 790 mi southwest of Flores Island.

Other systems
In addition to the named storms, there were several weak depressions during the season. As Agnes was moving over the southeastern United States, a tropical depression formed approximately 400 mi southwest of Bermuda on June 19. It moved northeastward and headed toward the island. The depression dissipated later the following day. The next tropical Depression developed offshore North Florida on July 10. Moving generally northward, the system made landfall near Cape Fear in North Carolina on July 12. The depression dissipated over Virginia about two days later. Generally light rainfall was reported in several states, though 8 in of precipitation was recorded on Cedar Island, North Carolina. Another tropical depression originated about 430 mi southwest of Flores Island in the Azores on July 16. It trekked slowly until July 19, at which time the system curved northeastward. Late the following day, the depression dissipated about 225 mi west of Flores Island. On July 31, a tropical depression formed about 515 mi southeast of Bermuda. The depression moved southwestward, toward the Bahamas and Lesser Antilles, but dissipated about 225 mi northeast of Turks and Caicos Islands on August 3.

A tropical depression developed over Senegal on August 5. Tracking westward, the depression passed south of Cape Verde before dissipating southwest of the islands on August 8. Four days later, another tropical depression originated about 175 mi east-southeast of Charleston, South Carolina. It moved slowly northeastward and intensified slightly, but dissipated about 210 mi southeast of Cape Hatteras, North Carolina, on August 15. The tenth tropical depression formed on August 16 while offshore Senegal. Moving generally westward, the cyclone crossed through Cape Verde and struck the islands of Fogo and Santiago. By August 18, the depression dissipated. Another tropical depression developed about 800 mi east-southeast of Bermuda on September 3. The system moved northeastward toward the Azores, but degenerated about 750 mi southwest of Flores Island on September 5. The next tropical depression formed on September 20 while located about 570 mi west-southwest of Cape Verde. The storm tracked generally westward, but then began moving west-northwestward on September 21. Three days later, the depression dissipated about 890 mi east-northeast of Barbados.

On October 1, a tropical depression originated about 700 mi east-southeast of Bermuda. The depression tracked generally northward and dissipated about 505 mi south-southeast of Cape Race, Newfoundland, on October 3. Another tropical depression formed about 120 mi west of Bolama, Guinea-Bissau, on October 5. The depression moved generally westward, before curving to the northwest on October 8. Five days later, it turned northward while well northeast of the Lesser Antilles. By October 14, the system began moving north-northeast. The depression dissipated about 800 mi east-northeast of Bermuda on the following day. Yet another tropical depression formed about 445 mi southwest of Brava, Cape Verde, on October 16. Initially the depression moved generally west-northwestward and dissipated about halfway between Barbados and Cape Verde.

Storm names
The following list of names was used for named tropical storms that formed in the north Atlantic in 1972. Storms were named Agnes, Betty and Dawn for the first (and only, in the case of Agnes) time in 1972.

The NATO phonetic alphabet (below) was used to designates subtropical cyclones that formed in the north Atlantic in 1972. Subtropical Storm Bravo became Betty after acquiring tropical characteristics.

Retirement
After the end of the 1972 Atlantic hurricane season, the name Agnes was retired due to the amount of damage and loss of life.

Season effects
This is a table of all of the storms that formed in the 1972 Atlantic hurricane season. It includes their name, duration, peak classification and intensities, areas affected, damage, and death totals. Deaths in parentheses are additional and indirect (an example of an indirect death would be a traffic accident), but were still related to that storm. Damage and deaths include totals while the storm was extratropical, a wave, or a low, and all of the damage figures are in 1972 USD.