1972 Atlantic hurricane season

Cool water and strong shear in the tropics

The National Hurricane Center called 1972 the least active Atlantic season since 1930, even though forecasters counted about as many tropical wave seedlings as in the busy 1971 season. Its review gave several reasons. Sea surface temperatures from the Lesser Antilles to Africa ran below normal for much of the season while the far eastern Pacific ran warm. Strong, steady upper westerlies kept vertical shear high over the usual breeding grounds, and the intertropical convergence zone never shifted north as the season went on. A strong El Niño suppressed activity.

Agnes was the only storm to form in the tropics. Every other system grew in temperate latitudes out of or beside a baroclinic zone, where shear was weaker and sea temperatures more favorable. The NHC counted four named storms, three of which reached hurricane strength for only 8 hurricane days between them, and a lowest pressure of 976 mb for the whole year.

The site's 7 tropical storms include the subtropical storms Alpha, Charlie and Delta alongside the four named storms, because the archive counts any system with one-minute winds of 34 kt or more. The site keeps three hurricanes, Agnes, Betty and Dawn. The current best track lists only two, leaving Dawn below hurricane strength, with Betty the stronger of the pair.

Alfa, Bravo, Charlie and Delta

For the first time, the NHC issued bulletins on subtropical cyclones and gave them names from the phonetic alphabet. Alfa grew out of a large cold low off Florida and developed a small, intense center that came ashore just south of Brunswick, Georgia, late on 27 May with 45 kt winds over a very small area. Waves reached 20 feet off the Virginia capes, beaches eroded on the Outer Banks, and two people drowned in rough surf after the storm.

Charlie formed on 19 September as a small, round cyclone and turned into a near-record extratropical storm with a 946 mb pressure. Delta formed from a cold low in the mid-Atlantic on 1 November and meandered for five days before losing its identity. The fourth system, Bravo, grew into Hurricane Betty.

Hurricane Agnes and the floods of June

Agnes formed from a disturbance near Cozumel on 14 June, drifted east and reached storm strength that night. Torrential rain in western Cuba caused major damage and killed seven people. With a circulation about 1,000 nautical miles across, one of the largest June hurricanes on record, Agnes became a hurricane on 18 June and peaked at 75 kt early on 19 June in the site's archive. It weakened before landfall near Cape San Blas that afternoon. Reconnaissance measured 65 kt just before landfall, while the strongest land gust was 48 kt at Apalachicola. Tides rose 6.4 feet at Apalachicola and 7 feet at Cedar Key.

Agnes fell to a depression over Georgia on 20 June. Then an approaching trough fed it fresh baroclinic energy. A second low formed to its west over the Carolinas, the Agnes center moved offshore near Norfolk, and its lowest pressure of 977 mb came just off New Jersey on 22 June before it crossed western Long Island. Six to 10 inches of rain fell over North Carolina and New York, and 10 to 14 inches over wide parts of Virginia, Maryland and Pennsylvania, onto ground already saturated.

The NHC put U.S. property damage near $3.1 billion and called Agnes the greatest natural disaster yet in dollar terms, above Camille and Betsy combined. It reported that fewer than 120 people died in the United States. In Florida, tidal flooding, 15 tornadoes and windstorms caused the damage outside the river floods, and windstorms around Lake Okeechobee accounted for six of the nine deaths in the state. Other totals give a lower damage figure of at least $2.1 billion in 1972 dollars and 131 deaths across the storm's path, mostly from flooding in Pennsylvania and New York.

Betty, Carrie and Dawn off the East Coast

Subtropical Storm Bravo formed in an old frontal zone north-northwest of Bermuda on 22 August, only 30 to 40 miles across at first. By 27 August reconnaissance found a classic eyewall about 800 nautical miles west of the Azores, and Bravo became Hurricane Betty. The NHC review wrote that no storm had first become a hurricane at a higher latitude. Betty peaked at 90 kt and 976 mb late that day, came within 150 nautical miles of Corvo, and turned extratropical on 1 September with no reported deaths or damage.

Tropical Storm Carrie grew from a cold-core low off southeast Florida, passed Cape Hatteras with 45 to 50 kt winds, weakened in shear and then strengthened again as it lost its tropical traits. Its center crossed the coast near Eastport, Maine, on 4 September. Gusts reached 73 kt at Point Judith, Rhode Island, 6 to 9 inches of rain fell on Cape Cod, and four people died on that coast when small boats capsized, many at Rockport, Massachusetts. The NHC estimated $1.78 million in damage, mostly in Massachusetts.

Hurricane Dawn formed off southeast Florida in early September and reached minimal hurricane strength east of Cape Hatteras on 7 September. A cold low that developed near Hatteras then pulled it west and south to about 32°N before it drifted toward Georgia and South Carolina and weakened. No forecast technique anticipated that turn, and Dawn's 24-hour track errors averaged 156 nautical miles, the largest in recent years. It caused no significant damage or deaths.