The storm is expected to hit southwestern city of Khaosiung, home to 2.7 million people, early on Thursday.
Taiwan has shut down ahead of the arrival of Typhoon Krathon closing offices and schools, evacuating thousands and cancelling flights and ferry services.
Krathon, with sustained wind speeds of 173km (107 miles) per hour and gusts of up to 209km/h (130mph), is expected to strike the southwestern port city of Kaohsiung in the early hours of Thursday and has already brought torrential rain and strong winds.
The Central Weather Administration said it was located about 160km (99 miles) southwest of Kaohsiung as of 7.00am on Wednesday (23:00 GMT on Tuesday).
Kaohsiung Mayor Chen Chi-mai asked the city’s 2.7 million residents to stay indoors unless necessary and to avoid flood- and landslide-prone areas near rivers, the sea and the mountains. Up to 80cm (31 inches) of rain has been forecast in surrounding mountainous areas.
Chen warned Krathon would be “no less powerful” than 1977’s Typhoon Thelma, which devastated the city, leaving 37 dead and 298 injured.
Typhoons rarely strike Taiwan’s densely populated west coast, usually hitting the mountainous, eastern side of the island facing the Pacific. In July, Typhoon Gaemi triggered landslides and flooding, killing at least 11 people.
All cities and counties in Taiwan declared a day off on Wednesday. The Ministry of Interior said that nearly 10,000 people had been evacuated from at-risk areas as a precaution. Domestic and many international flights were cancelled.
Chou Yi-tang, a government official working in Khaosiung’s Siaogang district where the airport is located, said the typhoon had brought back bad memories of Thelma for the older generation.
In his district, more than 700 sandbags had been distributed, which is a record for a typhoon, while authorities were making more to meet demand, Chou said. Storm drains were also being cleared to reduce the risk of flooding.
“We were hit directly by the eyewall,” he said of the events almost five decades ago. “Power was out for two weeks and no water for almost a month. It was disastrous.”
Taiwan’s Ministry of Defence said it had put nearly 40,000 troops on standby.
Across Taiwan, 35 typhoon-related injuries had been reported as of late Tuesday, authorities said without providing details.
Typhoons are common around the Asia Pacific at this time of year.
However, a recent study showed that they are increasingly forming closer to coastlines, intensifying more rapidly and lasting longer over land due to climate change.
Krathon had already wreaked havoc in the northern Philippines, killing at least one person, forcing about 5,000 people from their homes and causing widespread flooding.