Nearly 2 million people in southern China have been evacuated as a powerful typhoon hurtles into one of the world?s most densely populated coasts, having already unleashed deadly flooding in Taiwan.

Typhoon Ragasa, which a few days ago was the strongest storm on earth so far this year, brought finance hub Hong Kong and swathes of southern China to a standstill on Wednesday, after barreling through remote islands in the Philippines and mountainous regions of Taiwan.

Packing hurricane-force winds, the storm has left a trail of damage, triggering landslides, flooding and huge waves, and is now bearing down on China?s Guangdong province, where massive cities like Shenzhen and Guangzhou are located.

In Taiwan, at least 17 people are dead and rescuers were scrambling to locate 17 others still missing Wednesday afternoon local time after a natural dam holding back a recently formed lake collapsed a day earlier, unleashing 68 million tons of water and flooding the nearby Guangfu township.

Videos from the town, in the mountainous eastern Hualien County, show a torrent of water rushing through the streets, with cars swept away and residents sheltering on higher floors as the lower levels of their homes become inundated.

Debris from a landslide in July had formed the natural dam, and authorities had been warning for weeks the remote lake could overflow by October. At a news conference on Wednesday, officials said assessments showed it wasn?t feasible to dredge, siphon or otherwise remove the dam barrier - so they opted to monitor the situation instead.

Before the typhoon hit, authorities said they had issued multiple warnings and evacuation advisories to residents who could be impacted if the lake overflowed.

But their October prediction didn?t take heavy rainfall into account ? and any strong typhoons could have sped up that process, said Kuo-Lung Wang, a professor at Taiwan?s National Chi Nan University.

A large bridge in Hualien was also washed away by the rush of water following the collapse of the natural dam.

Southern China battered

The Philippines, Taiwan and southern China experience multiple typhoons annually, but the human-caused climate crisis has made storms more unpredictable and extreme.

As the storm approached the international finance hub of Hong Kong early Wednesday, it brought lashing winds that felled trees and ripped scaffolding off buildings, reaching maximum gusts of 168 kilometers per hour (104.39 mph). One CNN reporter on the ground saw sea swells pounding the sidewalk near Hong Kong?s iconic harbor.

Video circulating on social media showed storm surges shattering the glass doors of the Fullerton Ocean Park Hotel, a luxury seaside resort, with huge waves gushing into the lobby and sweeping people off their feet.

In a statement to CNN, the hotel said no injuries were reported and that the government had ?immediately? mobilized resources to respond.

Across all of Hong Kong, at least 90 people were injured as a result of the typhoon, according to authorities. A total of 885 people took refuge in temporary shelters across the territory, the government said.

Photos and video from Macao showed waist-deep water flooding the streets of the tourism and gambling hub, often dubbed the most densely populated city on earth.

The winds have prompted Hong Kong and Macao ? together home to more than 8 million people ? to issue their highest hurricane warning signal, with schools, businesses and public transit largely closed, including the city?s airport, one of Asia?s busiest. Storm surges of more than 3 meters were recorded in parts of the city by the Hong Kong Observatory.

Footage from Shenzhen, just across the border from Hong Kong, showed massive waves crashing into a coastal park Tuesday night, with winds reaching 181.44 kilometers per hour (112.4 mph).

Other cities along the southern coast of China were bracing for impact, too, with authorities triggering measures to protect those most at risk from storm surges and landslides.

The storm had the equivalent strength of a Category 3 hurricane as it edged towards landfall on mainland China Wednesday afternoon local time.

The country?s southern Guangdong province evacuated 1.89 million people by Tuesday night ahead of the typhoon?s arrival, according to the provincial emergency management department.

In Zhuhai, a coastal city neighboring Macao, residents of seaside high-rises were ordered to evacuate on Tuesday afternoon, according to state media, with many taking refuge with relatives, checking into hotels, or moving into temporary government shelters like school gyms.

One longtime resident, who relocated with her family to a school gymnasium, told local outlet Hongxing News it was the first time in her three decades living in Zhuhai that she had ever been evacuated.

More than 10,000 vessels in Guangdong were relocated to safer waters to avoid the storm, and more than 38,000 firefighters are on standby, according to state-run outlet Xinhua.

Strong track record of preparing for typhoons

Though this region is highly populated, with tens of millions potentially impacted by the typhoon, it?s also well-prepared.

These cities are frequently in storm paths and have developed sophisticated infrastructure to combat weather-related dangers ? including a vast $3.8 billion drainage network that has saved Hong Kong from floods that decades ago routinely cost lives and caused widespread destruction.This year has been particularly stormy. Hong Kong typically experiences about six typhoons annually, but Ragasa marks the ninth typhoon so far this year, according to the City University of Hong Kong.

Climate change is making storms of this scale not only more common but more powerful too, according to Johnny Chan, an atmospheric scientist at the Asia-Pacific Typhoon Collaborative Research Centre.

?Because of global warming, you will have more moisture in the atmosphere and (the) water temperature is also high, therefore ? once the storm develops, it has more energy,? said Chan.

He warned cities in Asia would need to continually update their building codes to handle stronger winds, higher sea levels and more intense typhoons.

?Most of the building codes were designed based on the past data, but the past data would not be accurate anymore for the future,? he said.

Cleanup efforts are now underway in the Philippines ? where the typhoon had been the equivalent of a Category 5 hurricane when it struck northern parts of the country on Monday.

At least seven fisherman were killed after a boat overturned off the coast off Luzon on Monday, according to the state-run Philippine Information Agency.

Another storm called Opong is now intensifying in the Philippines in the aftermath of Ragasa and the typhoon season still has many months left. (CNN)

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