Typhoon Helen was the most destructive tropical cyclone to strike Japan during the 1972 Pacific typhoon season. Originating from a tropical disturbance on September 11 near the Northern Mariana Islands, Helen gradually intensified as it moved northwestward. By September 14, it reached typhoon strength and soon turned northeast towards Japan. Accelerating due to a trough over the East China Sea, Helen rapidly approached the country and made landfall near Cape Kushimoto as a Category 3-equivalent typhoon on the Saffir–Simpson Hurricane Scale. Later that day, a weakened Helen emerged into the Sea of Japan. After merging with an upper-level low, the storm transitioned into an extratropical cyclone on September 19 and was last noted two days later after moving through southern Hokkaido.