TROPICAL CYCLONES IN 2008

3.5	Typhoon Hagupit (0814): 19 - 25 September 2008

Hagupit was the fifth tropical cyclone that necessitated the issuance of tropical cyclone warning signals in Hong Kong in 2008. It was also the fourth tropical cyclone that necessitated the issuance of the No. 8 Gale or Storm Signal in the year, making this year the one with the most No. 8 Signals since 1999.

Hagupit formed as a tropical depression over the western North Pacific about 2 540 km east-southeast of Hong Kong on the morning of 19 September and moved west-southwestwards. It intensified into a tropical storm on the early hours of 20 September, and a severe tropical storm that afternoon and moved west-northwestwards. Hagupit moved northwestwards and intensified further into a typhoon on 21 September. Turning to move west-northwestwards, Hagupit crossed the Balintang Channel on 22 September and entered the South China Sea that evening. Hagupit moved at a speed close to 30 km/h across the northern part of the South China Sea on 23 September and passed about 180 km south-southwest of Hong Kong from about 10 to 11 p.m. on 23 September. While crossing the northern part of the South China Sea, Hagupit attained an estimated maximum sustained wind speed of about 175 km/h near the centre, and was the most intense typhoon to affect Hong Kong in 2008. Hagupit made landfall near Dianbai in western Guangdong on the morning of 24 September. It weakened into a severe tropical storm that afternoon and further into a tropical storm in the evening. Hagupit weakened into a tropical depression on the small hours of 25 September and into an area of low pressure over northern Vietnam that morning. According to press reports, nine people were killed in the Philippines. In Guangdong and Guangxi, at least five people were killed and two others missing. About 8.5 million people were affected, over 14000 houses collapsed and the direct economic losses were around RMB$ 5.8 billion. Hagupit triggered floods and landslides in northern Vietnam, where at least 25 people were killed, seven missing and 20 others injured.

In Hong Kong, the Standby Signal No. 1 was issued at 6:40 p.m. on 22 September when Hagupit was about 780 km east-southeast of Hong Kong. Local winds were light to moderate northwesterlies on 22 September. As Hagupit moved closer to Hong Kong, the Strong Wind Signal No. 3 was issued at 10:25 a.m. on 23 September when Hagupit was about 350 km to the southeast. Local winds freshened from the north and became strong on high grounds that morning. As Hagupit was a relatively fast moving typhoon, local winds strengthened rapidly in the afternoon, becoming generally strong with gales on high grounds. The No. 8 NE Gale or Storm Signal was issued at 6:00 p.m. that day when Hagupit was about 210 km to the south-southeast. Gale force northeasterlies to easterlies prevailed over Hong Kong that night, with storm force winds offshore and on high grounds, and occasionally reaching hurricane force on high grounds. Sustained gale or storm force winds were attained in four of the eight reference stations in the network of reference anemometers in the tropical cyclone warning system. The maximum 10-minute mean wind recorded at Cheung Chau was 113 km/h, which was the highest among the eight stations. With Hagupit starting to move away from Hong Kong on the early hours of 24 September, local winds turned to the southeast and the No. 8 SE Gale or Storm Signal was issued at 12:40 a.m. on 24 September. The gale or storm force winds in Hong Kong gradually subsided thereafter and the No. 8 Signal was replaced by the No. 3 Strong Wind Signal at 6:30 a.m. in the morning. All tropical cyclone warning signals were cancelled at 12:50 p.m. that day as Hagupit moved further away and local winds continued to subside.

During the passage of Hagupit, the lowest instantaneous mean sea-level pressures recorded at some selected stations were as follows :-

Station	Lowest instantaneous mean sea-level pressure	Date/Month	Time
Hong Kong Observatory Headquarters	992.2 hPa	23/9	5.49 - 6.57 p.m.
Waglan Island	990.4 hPa	23/9	6.51 - 6.55 p.m.
Cheung Chau	992.0 hPa	23/9	8.23 p.m.
Hong Kong International Airport