The tropical cyclone Mangkhut struck Hong Kong on Sunday (16/9/18).
The observatory issued a tenth signal at 9:40, two hours after signal 9, with an average wind speed of 118 km / h.
Science officer Lee Tsz-cheung said the T10 signal was valid for several hours and a rain storm warning was also given.
"According to our current estimates, the water in Victoria Harbor will increase by about 3.5 meters above sea level, according to data from this afternoon's chart," said Lee, who belongs to the tribe.
In addition, the observatory also warned that the water level had increased about four meters in the usual Tai O, Lantau.