Haiyan, potentially the strongest recorded typhoon to make landfall, slammed into the Philippines' central islands on Friday, forcing millions of people to flee to safer ground or take refuge in storm shelters.
The category-five super typhoon whipped up giant waves as high as 4-5 metres (12-15 feet) that lashed the islands of Leyte and Samar, and was on track to carve a path through popular holiday destinations.
Haiyan is also forecast to pass close to the Philippines' second-largest city Cebu, home to around 2.5 million people, and also buffet the capital Manila.
"The super typhoon likely made landfall with winds near 195 mph (313 kph). This makes Haiyan the strongest tropical cyclone (typhoon) on record to make landfall," said Jeff Masters, a hurricane expert and director of meteorology at U.S.-based Weather Underground.
Super typhoons and cyclones with winds around 300 kph are so powerful they can blow apart storm-proof shelters due to the huge pressures they create, which can suck walls out and blow roofs off buildings, according to engineers.
About a million people were in areas of shelter in more than 20 provinces, after Philippine President Benigno Aquino on Thursday appealed to people in Haiyan's path to evacuate from danger spots, such as river banks, coastal villages and mountain slopes.
"We are fearful because there is talk that the sea will rise," an elementary school teacher in Southern Leyte province who only gave her name as Feliza told a radio station.
"We can feel the powerful winds, our school is now packed with evacuees. Trees in coastal areas have already fallen."
Authorities stopped ferry services and fishing operations, while nearly 200 local flights had been suspended. Commuter bus services were also halted as the storm dumped torrential rain and ripped galvanized iron roofs off buildings and houses.
Schools, offices and shops in the central Philippines were closed, with hospitals, soldiers and emergency workers on standby for rescue operations.
"We can hear the winds howling but the rains are not too strong. We have encountered several distress calls regarding fallen trees and power lines cut. We don't have power now," Samar Vice Governor Stephen James Tan said in a radio interview.
More than 41,000 people have been evacuated in his province, one of the country's poorest, said Tan.
The state weather bureau said Haiyan is expected to pass over the Philippines late on Saturday and then move into the South China Sea, where it could become even stronger and threaten Vietnam or China.
The world's strongest recorded typhoon, cyclone or hurricane to previously make landfall was Hurricane Camille in 1969, which hit Mississippi with 190 mph winds, said Weather Underground's Masters.
An average of 20 typhoons slam into the Philippines every year. In 2011, typhoon Washi killed 1,200 people, displaced 300,000 and destroyed more than 10,000 homes.
Typhoon Bopha last year flattened three coastal towns on the southern island of Mindanao, killing 1,100 people and wreaking damage estimated at $1.04 billion.
In September, category-five typhoon Usagi, with winds gusting of up to 240 kph (149 mph), battered the northern island of Batanes before causing damage in southern China.