AFP
Packing estimated maximum wind gusts of 195 mph (315 kph), the storm is projected to roar between the Philippines and Taiwan before smashing into the southern Chinese coast later in the weekend.
At 0600 GMT Friday it was centred 1,120 kilometres southeast of Hong Kong, officials in the Chinese territory said.
"It is the strongest typhoon in the west Pacific region this year," a
Philippine authorities evacuated some 240 people in the northern agricultural province of Tarlac, while ferries were restricted to their ports, stranding travellers.
A signal four alert was issued for the Batanes island group in the extreme north of the country, warning large trees could be uprooted, plantations flattened and power and communications infrastructure knocked out.
Emergency relief services were also put on heightened alert, with the Red Cross already stockpiling first aid kits and food packs in some areas.
"Damage to affected communities can be very heavy," the Philippine Atmospheric, Geophysical and Astronomical Services Administration said. "The situation is potentially very destructive to communities. All travel and outdoor activities should be cancelled."
The country's National Disaster Risk Reduction and Management Council said Usagi would cause intense rainfall of 10-20 millimetres per hour within a 700-kilometre range.
Hong Kong officials warned of worsening weather in the southern Chinese territory.
"Weather will deteriorate significantly with strengthening winds and rough seas," the Hong Kong observatory said. Its tropical cyclone track map showed the storm would hit the city after 8:00 pm (1200 GMT) on Sunday.
AFP
The typhoon is expected to be downgraded to "severe" by the time it makes landfall in the territory, according to the observatory -- still enough to stop metro and ferry services and curtail air travel.
Typhoon Usagi is set to brush the southern tip of Taiwan on Saturday morning, expected to bring fierce winds and torrential rains, possibly leading to landslides.
Taiwan's defence ministry deployed more than 1,600 soldiers in "high risk" areas prone to flooding and landslides while placing 24,000 others on standby.
The island's weather bureau issued a warning to the residents of Taitung, Kaohsiung and the Pingtung areas to take special precautions, as television news footage showed people surfing on waves whipped up by Usagi.
Authorities in the southern city of Kaohsiung deflated an 18-metre-tall (60 feet) yellow duck, a slightly larger version of the one that recently captivated people in Hong Kong, a day after it arrived in the city, drawing tens of thousands of visitors.
And workers in New Taipei City removed tourist boats and a floating bridge from the Hsintien river in anticipation of the storm.
Mainland Chinese weather authorities have issued a "yellow" alert, state media reported, the third-highest on its four-tier warning system, according to the official official Xinhua news agency.
Disaster officials urged local authorities to prepare for emergencies while telling people to be wary of landslides, falling stones and floods.
China's State Oceanic Administration expects Usagi to hit the coast on Sunday evening.
Typhoon Utor, which struck last month, killed eight people in the Philippines and left tens of thousands displaced and whole towns badly damaged when it raked across the north of the main island of Luzon.
Utor, which also led to deaths in China, forced the closure of financial markets, schools and businesses in Hong Kong, disrupting hundreds of flights and also caused the sinking of a 190-metre-long cargo ship to the city, but all 21 crew were rescued.
A super typhoon is the most intense tropical cyclone, with a maximum sustained wind speed reaching 185 km/h or above.