In the past hour, the maximum sustained winds recorded at Tate's Cairn, Waglan Island and Cheung Chau were 114, 94 and 63 kilometers per hour with maximum gusts 149, 113 and 98 kilometers per hour respectively.
As the storm passed south of Hong Kong, trees were snapped in half and roads blocked, while some windows in tower blocks were smashed and skyscrapers swayed, as they are created to do in intense gales.
Hundreds of flights were canceled.
Hong Kong's government has warned employers they could face prosecution if they don't recognise the dangers in demanding their employees come to work, or if they threatened to dock workers' annual leave for sheltering during the storm.
Hong Kong authorities lifted the storm alert to its highest level on Sunday as typhoon Mangkhut was fast approaching, bringing the city to a standstill as residents prepared for the threat of heavy rain, storm surges and flooding. "The wind is so strong". "Each department must have a sense of crisis, make a comprehensive assessment and plan, and prepare for the worst". Airlines such as flagship carrier Cathay Pacific cancelled many flights last week. The city of Shenzhen also cancelled all flights between Sunday and early Monday morning. Hong Kong's famous skyline, filled with massive buildings jutting up from the hill, was nearly completely obscured as squalls roared through, however visibility has since improved.
Macao has been extra cautious this time around.
The government and casinos are taking extra precautions after Macau was battered by Typhoon Hato a year ago, which left 12 dead.
Residents were told to avoid Hong Kong's harbors, including the iconic Victoria Harbor, where storm surges have caused the water level to rise dramatically.
The damage in China is still unclear, but almost half a million people have reportedly been evacuated from the port and surrounding areas in Mangkhut's path.
Chinese media reported that more than 2.45 million people had been evacuated in mainland Guangdong province.
Earlier on Saturday, it plowed into the Philippines, killing at least two people and flattening homes in small towns and villages on the northern island of Luzon.
The number of people killed by the typhoon increased as more landslide victims were discovered, said police.
Overall, at least 64 people have died in typhoon-related incidents in the northern Philippines, mostly from landslides and collapsed houses, according to the national police.
In 2013, Typhoon Haiyan left more than 7,300 people dead or missing, flattened villages and displaced more than 5 million in the central Philippines.
Thousands of people have been evacuated from Guangdong, where Mangkhut is due to strike later on Sunday.
Two rescue workers were killed while trying to free people trapped in a landslide in the mountainous Cordillera region, said Ricardo Jalad, head of the nation's disaster agency.