A once-in-a-decade typhoon threatened Japan on Tuesday forcing the cancellation of flights and trains and disrupting oil shipments as it made its way across the Pacific directly towards the capital, Tokyo.

Typhoon Wipha is expected to make landfall right around the morning rush hour on Wednesday, bringing hurricane-force winds to the metropolitan area of 30 million people.

The centre of the storm was 860 km (535 miles) southwest of Tokyo at 0800 GMT, the Japan Meteorological Agency said on its website. It was moving north-northeast at 35 kph (22 mph).

The storm had weakened as it headed north over the sea but was still packing sustained winds of about 140 kph (87 mph) with gusts as high as 194 kph (120 mph), the agency said.

The agency issued warnings for Tokyo of heavy rain, flooding and gales, and advised people to be prepared to leave their homes quickly and to avoid unnecessary travel.

A spokesman for the agency said the storm was a “once in a decade event” and the strongest cyclone to approach eastern Japan since October 2004.

That cyclone triggered floods and landslides that killed almost 100 people, forced thousands to evacuate their homes and caused billions of dollars in damage.

Four Japanese oil refining companies said they suspended marine berth shipments in eastern Japan as the typhoon approached but there was no impact on refining operations.

The affected facilities are Idemitsu Kosan Co.’s Chiba and Aichi refineries, JX Holdings Inc’s Negishi, Kashima and Sendai refineries, Fuji Oil Co.’s Sodegaura refinery and Cosmo Oil Co.’s Chiba refinery.

Japan Airlines Co. cancelled 183 domestic flights on Tuesday and Wednesday, mostly from Tokyo’s Haneda airport. Rival ANA Holdings Inc. halted 210 flights in Japan with three international flights also cancelled. The combined cancellations will affect 60,850 passengers, the airlines said.

East Japan Railway Co said it had cancelled 31 bullet trains going north and west from Tokyo.

Nissan Motor Co. said it was cancelling the Wednesday morning shift at its Oppama and Yokohama plants south of Tokyo. Oppama makes the all-electric Leaf and other models.