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How do Gulf Stream rings form?

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Map of the North Atlantic Ocean showing major ocean currents, with warm currents like the Gulf Stream and North Atlantic Drift highlighted in pink and cold currents in blue. Arrows indicate current directions and relative speeds, connecting the eastern coasts of North America, the western coasts of Europe and Africa, and the Arctic region. — Gulf Stream Major warm and cold currents of the North Atlantic Ocean.

Gulf Stream rings are eddy structures that develop when meanders in the Gulf Stream pinch off and separate from the main current east of Cape Hatteras. These rings are categorized by their core temperature and the direction in which they pinch off:1

Warm-core rings: These form when meanders pinch off on the continental slope side of the Gulf Stream. They consist of warm waters from the Gulf Stream and the Sargasso Sea, typically measure 100 to 300 km (62 to 186 miles) in diameter, and rotate clockwise. They generally move westward and are reabsorbed into the Gulf Stream after about six months.1
Cold-core rings: These form when meanders pinch off to the south of the Gulf Stream. Composed of a mixture of Gulf Stream and continental slope waters, they are slightly larger (200 to 300 km, or 124 to 186 miles, in diameter) and rotate counterclockwise. They typically move southwestward into the Sargasso Sea and have longer lifetimes of one to two years.1