Hong Kong (AFP) - Tens of millions of people in Hong Kong, Shenzhen and other southern Chinese megacities sheltered indoors Friday as Super Typhoon Saola threatened to become the strongest storm to hit the region in decades.

Hundreds of flights were cancelled across the region, the start of the school year was delayed in Hong Kong, and the rain-drenched finance hub’s streets were deserted.

China’s national weather office had predicted Saola “may become the strongest typhoon to make landfall in the Pearl River Delta since 1949”, referring to a low-lying region that includes Hong Kong, Macau and Guangdong province.

With a direct hit possible, authorities in Hong Kong raised the warning level on Friday evening to the city’s highest – “T10” – which had only been issued 16 times since World War II before Saola.

“Do not go outside and stay away from exposed windows and doors. Make sure you have a safe place to shelter and be prepared for the change in wind directions,” the Hong Kong Observatory warned in a bulletin issued at 8:15 pm (1215 GMT).

Packing sustained winds of 210 km (130 miles) per hour, Saola’s impact poses “a high threat to Hong Kong”, and is expected to skirt the city in the next few hours.

“Members of the public should stay on high alert. You are advised to remain where you are if protected and be prepared for destructive winds,” the observatory said.

It added that “the maximum water level may reach a historical record”, warning that “there will be serious flooding”.

The last time Hong Kong issued a T10 warning was in 2018, when Typhoon Mangkhut slammed into the city, shredding trees and unleashing floods, and leaving more than 300 people injured.

In mainland China, Mangkhut killed six people and impacted the lives of more than three million others.

Neighbouring Shenzhen – home to 17.7 million people – in southern Guangdong province opened shelters for people to take refuge, as it halted public transport.

Trains in and out of Guangdong were also suspended until 6 pm Saturday, while the national flood defence agency raised its emergency response for prevention to its second-highest level.

“It’s going to affect our life,” said Wu Wenlai, 43, who had to close his restaurant in a Shenzhen suburb.

“My eldest son was planning to fly to Chengdu today for university and his flight has been cancelled now.”

- More intense typhoons -

Southern China is frequently hit in summer and autumn by typhoons that form in the warm oceans east of the Philippines and then travel west.

Climate change has increased the intensity of tropical storms, with more rain and stronger gusts leading to flash floods and coastal damage, experts say.

In Hong Kong, authorities received at least seven confirmed cases of flooding, as well as more than two dozen reports of downed trees.

Businesses taped up their glass displays and windows.

In eastern Heng Fa Chuen – a coastal residential area and the site of devastation during 2018’s Typhoon Mangkhut – officers in orange vests urged storm-watchers to go home, as trees leaned sideways from the heavy gusts.

In the low-lying fishing village of Lei Yue Mun – which is prone to flooding – water seeped into shops, prompting residents to set up sandbags and board up doors.

“I hope we can save the tools needed for our business, like the fridge. We elevated them so the water wouldn’t damage the (electronics),” a restaurant operator surnamed Lee told a local TV station.

Neighbouring casino hub Macau – which had issued its third-highest typhoon warning – is expected to raise it to the second-highest by 11 pm.

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