Death tolls could climb later in the day, with authorities having identified at least nine people missing as of Tuesday afternoon, including seven people at a submerged underground parking lot in Pohang.
More than 60,000 households nationwide lost power because of the typhoon.
As a precaution, authorities closed more than 600 schools nationwide, and local carriers grounded about 250 domestic flights – but service gradually resumed Tuesday as Hinnamnor headed towards Japan.
Typhoon warnings have been lifted across most parts of South Korea except in some regions, including the southern Ulsan, North Gyeongsang province and the eastern Gangwon province.
About 2,900 people are still evacuated, mostly in the southern regions.
The military has mobilised amphibious vehicles for rescue operations, the defence ministry said.
Earlier, President Yoon Suk-yeol convened response meetings and urged officials to take precautions until the typhoon is completely gone, his spokesperson said.
“Heavy rains, strong winds and a storm surge are expected until Tuesday,” the weather agency said, warning against “very” high waves in the coastal areas.
A spokesperson for Daewoo Shipbuilding & Marine Engineering said there were no incidents at its shipyard so far, and it halted production on Tuesday morning as planned.
Shipbuilder Hyundai Heavy Industries said it planned to resume work on Tuesday afternoon. Both shipyards were located in or near the path of the typhoon.
Steelmaker POSCO said a byproduct gas release at the company’s Pohang plant in the morning was caused by a typhoon-related power outage.