AN "extremely dangerous" super typhoon predicted to be the one of the strongest systems on record is tearing towards Hong Kong and the Philippines with up to 43 million people in the firing line.
Bureau of Meteorology Australia tropical climatologist Greg Browning told news.com.au Typhoon Mangkhut was equivalent to a Category 5 severe tropical cyclone and boasted maximum sustained winds of 205kph and gusts up to 285kph. It's "significantly stronger" than Hurricane Florence which is simultaneously hurtling towards the US as North Carolina locals evacuate in preparation for the onslaught.
"(Mangkhut is) at the top of the severe scale and relatively rare," Mr Browning said.
"It's extremely dangerous as it's a very large system with very strong winds and a potential storm surge over a large distance.
"There will be very heavy rainfall associated with it which has potential to cause widespread damage."
Mr Browning said Typhoon Mangkhut was the most powerful storm system to have developed on Earth this year but that it wasn't the strongest since records began in 1946, as has been reported internationally. Typhoon Haiyan - which killed more than 6,000 people when it lashed the Philippines with maximum sustained winds of 230kph and gusts of 325kp in 2013 - holds that record.
On Friday, Typhoon Mangkhut was in the Pacific, about 450km from the Philippines and expected to make landfall on Luzon Island on Saturday. More than four million Filippinos are reportedly in the path of the storm. Mr Browning said the super typhoon was then likely to continue tracking west to Hong Kong and southern China, putting millions more people at risk, on Sunday.
The system's "very destructive winds" and heavy rainfall are likely to cause infrastructure damage wherever it hits, according to Mr Browning.
"But the biggest killer of all with a system like this is typically the storm surge," he said.
"The region close to the typhoon's crossing can expect (to bare the brunt)."
The Hong Kong observatory's tracking system shows a 70 per cent probability that Typhoon Mangkhut could deviate within a 500km radius from its predicted position, leaving a lot of uncertainty over the next few days.
The system is already stronger than any of the 15 past severe or super typhoons that warranted the highest "No 10" warning sign, the South China Morning Post reports.
Countries across east and southeast Asia are issuing emergency alerts and ordering evacuations as both Mangkhut and a second storm, Typhoon Barijat hit the region. Around 12,000 people have been evacuated from low-lying parts of China's Guangdong province and shipping halted ahead of the arrival of Typhoon Barijat Thursday, according to state media.
Thousands of people in the path of Typhoon Manghut are being evacuated from their homes in the Philippines. Typhoon Mangkhut is forecast to hit the northeastern Cagayan province, where over four million people live, early on Saturday local time.
The military and police in northern Luzon have been placed on red alert - barring all troops from going on leave - so they can respond to emergencies in communities expected to bear the brunt of the typhoon.
Schools have been closed and bulldozers are on the ready for landslides with rescuers and troops on full alert.
With a massive rain cloud band 900km wide, combined with seasonal monsoon rains, the typhoon could bring heavy to intense rains that could set off landslides and flash floods, the forecasters said.
Storm warnings have been raised in 25 provinces across the main northern island of Luzon, restricting sea and air travel.
Office of Civil Defense chief Ricardo Jalad told an emergency meeting led by President Rodrigo Duterte that about 4.2 million people in Cagayan, nearby Isabela province and outlying regions are vulnerable to the most destructive effects near the typhoon's 125km-wide eye.
Nearly 48,000 houses in those high-risk areas are made of light materials and vulnerable to Mangkhut's ferocious winds.