Hurricane Sam was a strong, long-lived Cape Verde hurricane that threatened Bermuda, lasting from late September through early October. It was the fifth longest-lasting intense Atlantic hurricane, as measured by accumulated cyclone energy, since reliable records (for intense hurricanes) began in 1966. The eighteenth named storm, seventh hurricane, and fourth major hurricane of the 2021 Atlantic hurricane season, Sam originated from a tropical wave that departed from the western coast of Africa on September 19. The system developed into a tropical depression on September 22, as upper-level winds gradually became more favorable. Intensification was initially slow, with the depression strengthening into Tropical Storm Sam a day later. Soon afterward, the structure of the cyclone quickly impro