TROPICAL CYCLONES IN 2008
2.1 Review of TROPICAL CYCLONES IN 2008
| 2.1.1 | Tropical cyclones over the western North Pacific (including the South China Sea) |
In 2008, 24 tropical cyclones affected the western North Pacific and the South China Sea (i.e. the area bounded by the Equator, 45°N, 100°E and 180°). In the past 4 years (2005-2008), the annual number of tropical cyclones in this ocean basin has been less than the 30-year (1971-2000) average of 30. Throughout the year, 11 tropical cyclones attained typhoon strength, about 4 less than the normal figure.
The first tropical cyclone of the year formed in April. Figure 2.1 shows the monthly frequencies of the occurrence of tropical cyclones in the western North Pacific and the South China Sea in 2008.
During the year, eight tropical cyclones hit mainland China, four crossed over Taiwan, one skirted the coastal areas of southern Japan and the Ryukyu Islands, one made landfall over DPR Korea, three traversed the Philippines and another five made landfall over Vietnam.
The most intense tropical cyclone in 2008 was Jangmi (0815), which had a maximum wind speed of about 230 km/h and a minimum sea-level pressure of about 905 hPa (Table 4.1) when it was located over the western North Pacific to the east-southeast of Taiwan (Fig. 2.7).
The "Na Lina" phenomena over the Pacific occurred in early 2008 when the sea temperatures over the eastern and central equatorial Pacific were below normal. In the second half of the year, the "Nina Lina" conditions had weakened but the sea temperatures in the central Pacific were still slightly below normal. Furthermore, the subtropical ridge of high pressure over the western North Pacific was stronger than normal in summer and autumn, suppressing the convection over the area. Affected by such climatic conditions, the activity of the tropical cyclones in the western North Pacific and the South China Sea in 2008 was more concentrated over the western part of the region with 20 tropical cyclones formed in the region west of 140°E and only four to the east of 140°E. In addition, there were more tropical cyclones bringing gale force winds to Hong Kong and the typhoon season in Hong Kong started earlier than normal.
2.1.2 Tropical cyclones in Hong Kong's area of responsibility
Amongst the 24 tropical cyclones in 2008, 17 occurred inside Hong Kong's area of responsibility (i.e. the area bounded by 10, 30, 105 and 125), more than the 30-year (1971-2000) annual average of 15.4 (Table 2.1). Eight of these 17 tropical cyclones developed within Hong Kong's area of responsibility. Altogether, 472 tropical cyclone warnings to ships and vessels were issued by the Hong Kong Observatory in 2008 (Table 4.2).
2.1.3 Tropical cyclones over the South China Sea
Eleven tropical cyclones affected the South China Sea (i.e. the area bounded by 10, 25, 105 and 120) in 2008. Six of them formed over the area. Five moved into the area from the western North Pacific.
2.1.4 Tropical cyclones affecting Hong Kong
In 2008, the typhoon season started on 17 April when Typhoon Neoguri came within 800 km and necessitated the issuance of the Standby Signal No. 1. This was the second earliest onset time since 1946 (The earliest time of 9 April was set in 1967).
Six tropical cyclones, namely Typhoon Neoguri (0801) in April, Typhoon Fengshen (0806) in June, Severe Tropical Storm Kammuri (0809) and Typhoon Nuri (0812) in August, Typhoon Hagupit (0814) in September and Tropical Storm Higos (0817) in October affected Hong Kong (Figure 2.2), which was close to the normal number of 6 to 7 (Table 2.2). However, four of them, Fengshen, Kammuri, Nuri and Hagupit necessitated the issuance of the No. 8 Gale or Storm Signal or higher signals in Hong Kong, higher than the normal of one to two per year, and making 2008 the year with the most No. 8 Signals since 1999.
The centre of Nuri crossed Hong Kong in August 2008 and necessitated the issuance of the Increasing Gale or Storm Signal No. 9, the highest signal issued in 2008. Neoguri in April and Higos in October only necessitated the issuance of the Strong Wind Signal No. 3 and the Standby Signal No. 1 in Hong Kong respectively.
During the passage of Hagupit, the combined effect of storm surges and high tides resulted in a maximum sea level of 3.53 metres at Quarry Bay, the highest since Typhoon Wanda in September 1962.
2.1.5 Tropical cyclone rainfall
Tropical cyclone rainfall (the total rainfall recorded at the Hong Kong Observatory from the time when a tropical cyclone is centred within 600 km of Hong Kong to 72 hours after it has dissipated or moved farther than 600 km away from Hong Kong) in 2008 was 1,096.6 mm (Table 4.8.1). This is 47% above the normal of 745.5 mm and accounts for some 36% of the year's total rainfall of 3,066.2 mm.
Fengshen which affected Hong Kong on 23-25 June brought 342.6 mm of rainfall to Hong Kong, which was the tropical cyclone bringing the most rainfall to Hong Kong in 2008. Over 200 mm of rainfall were also recorded at the Hong Kong Observatory during the passages of Neoguri and Kammuri.
A monthly overview of tropical cyclones is given in this section. Detailed reports on tropical cyclones affecting Hong Kong are presented in Section 3.
JANUARY TO MARCH
No tropical cyclone occurred over the western North Pacific and the South China Sea from January to March.
APRIL
Neoguri (0801) formed as a tropical depression over the South China Sea about 360 km east of Nansha on 15 April. It moved generally west-northwestwards at first and intensified into a tropical storm that evening. Neoguri intensified into a severe tropical storm and turned onto a north-northwesterly track on the afternoon of 16 April, and intensified further into a typhoon that evening. It turned to a northerly track on the evening of 18 April. After skirting the northeastern tip of Hainan on the small hours of 19 April, Neoguri weakened into a severe tropical storm and moved north-northeastwards. Neoguri weakened further into a tropical storm that morning and made landfall at Dongping Town, Yangdong County, Guangdong that afternoon. Neoguri continued to weaken further into a tropical depression that night and then dissipated inland.
MAY
Rammasun (0802) formed as a tropical depression over the western North Pacific about 1,510 km east-southeast of Manila on 7 May and moved northwestwards. It intensified into a tropical storm and turned to move northwards the next day. On 9 May, Rammasun intensified first into a severe tropical storm, and then further into a typhoon. It turned to move north-northeastwards on 11 May, then weakened into a severe tropical storm and moved northeastwards the next day. Rammasun became an extra-tropical cyclone over the western North Pacific to the south of Tokyo on 13 May. Fig. 2.3 shows the satellite image of Rammasun.
Matmo (0803) formed as a tropical depression over the western North Pacific about 420 km northeast of Manila on 15 May and moved generally northeastwards. It intensified into a tropical storm on 16 May and then became an extra-tropical cyclone over the western North Pacific south of Japan that night.
Halong (0804) formed as a tropical depression over the central part of the South China Sea about 530 km west-southwest of Manila on 15 May and moved north-northeastwards. It intensified into a tropical storm and turned to move northeastwards on 16 May. It intensified into a severe tropical storm the next day. Halong weakened into a tropical storm after crossing Luzon on the night of 17 May and the small hours of 18 May. According to press reports, at least 44 people were killed in the Philippines. Halong re-intensified into a severe tropical storm on 19 May but weakened into a tropical storm on 20 May. Halong became an extra-tropical cyclone over the western North Pacific south of Japan that day.
Nakri (0805) developed into a tropical depression over the western North Pacific about 350 km north of Yap on 27 May and moved generally northwestwards. It intensified into a tropical storm that evening and a severe tropical storm the next day. Nakri intensified further into a typhoon on 29 May, and turned to move northwards on 31 May. Nakri then turned to move north-northeastwards to the southeast of Ryukyu Islands on 1 June. It turned further to move northeastwards on 2 June. Nakri weakened first into a severe tropical storm on 3 June and finally became an extratropical cyclone over the western North Pacific south of Japan during the day.
JUNE
Fengshen (0806) formed as a tropical depression over the western North Pacific about 1,440 km east-southeast of Manila on 18 June and moved west-northwestwards. It intensified first into a tropical storm and then a severe tropical storm the next day. After intensifying into a typhoon on 20 June, Fengshen started to cross the Philippines that afternoon, and entered the South China Sea on the evening of 22 June. It weakened into a severe tropical storm on 23 June and turned to move north-northwestwards the next day. On the morning of 25 June, Fengshen made landfall in Shenzhen after skirting to the east of Hong Kong. Fengshen weakened into a tropical storm that morning and further into a tropical depression that night. It finally weakened into an area of low pressure over Guangdong the next morning.
JULY
Kalmaegi (0807) formed as a tropical depression over the western North Pacific about 630 km southeast of Gaoxiong on 14 July and moved southwestwards slowly. Kalmaegi intensified into a tropical storm the next day. It turned to move generally north-northwestwards and intensified into a severe tropical storm on 16 July, and a typhoon the next day. Kalmaegi crossed northern Taiwan on the small hours of 18 July and weakened into a severe tropical storm. According to press reports, Kalmaegi brought torrential rain to Taiwan, triggering flash floods and landslides. Twenty people were killed and the agricultural losses exceeded NT$1 billion. Kalmaegi made landfall near Xiapu in northeastern Fujian that evening and weakened further into a tropical storm. Kalmaegi brought damage to parts of Fujian and the direct economic losses were around 300 million RMB. It turned to move north-northeastwards across Zhejiang and Jiangsu on 19 July and turned to move northeastwards the next day. Kalmaegi became an extra-tropical cyclone near DPR Korea on 21 July. Fig. 2.4 shows the satellite image of Kalmaegi.
Fung-wong (0808) formed as a tropical depression over the western North Pacific about 720 km southeast of Okinawa on 24 July and moved generally westwards. It intensified into a tropical storm on 25 July and a severe tropical storm the next day. Fung-wong intensified further into a typhoon on 27 July and turned to move northwestwards, crossing Taiwan on the morning of 28 July. According to press reports, two people were killed and six others injured in Taiwan and the agricultural damage exceeded NT$300 million. Fung-wong made landfall at Fuqing City, Fujian on the night of 28 July. It weakened first into a severe tropical storm and then a tropical storm on the following day. Fung-wong weakened into a tropical depression and subsequently into an area of low pressure overland on 30 July. Fung-wong brought rainstorms to southeastern China and triggered tornadoes in Jiangsu. At least six people were killed and over 40 others injured. Over 2 000 houses collapsed or were damaged and the direct economic losses were some 1.5 billion RMB. Fig. 2.5 shows the satellite image of Fung-wong.
AUGUST
Kammuri (0809) formed as a tropical depression over the South China Sea about 580 km southeast of Hong Kong on 4 August and moved west-northwestwards. It intensified into a tropical storm the next morning. On the small hours of 6 August, Kammuri intensified into a severe tropical storm and moved northwestwards. It turned to move westwards later that afternoon and made landfall at Yangxi County in western Guangdong that evening, and weakened into a tropical storm that night. Kammuri weakened into a tropical depression over northern Vietnam on the small hours of 8 August and further into an area of low pressure there that morning.
Phanfone (0810) formed as a tropical depression over the western North Pacific about 1,440 km southeast of Tokyo on 9 August and moved generally northeastwards. It intensified into a tropical storm on the afternoon of the following day. Phanfone became an extra-tropical cyclone over the western North Pacific to the east of Japan on 11 August.
Vongfong (0811) formed as a tropical depression over the western North Pacific about 710 km south-southwest of Osaka on 15 August and moved northeastwards. It intensified into a tropical storm that afternoon and turned to move generally east-northeastwards. Vongfong intensified further into a severe tropical storm on 16 August but weakened into a tropical storm the next day. It finally became an extra-tropical cyclone over the western North Pacific to the east of Japan on 18 August.
Nuri (0812) formed as a tropical depression over the western North Pacific about 1 730 km east of Manila on the evening of 17 August and moved westwards. It intensified first into a tropical storm and then a severe tropical storm the next day, and further into a typhoon and moved west-northwestwards on 19 August. Nuri entered the South China Sea on the evening of 20 August and turned to move northwestwards on the next evening. Nuri weakened into a severe tropical storm and crossed Hong Kong after making landfall at Sai Kung, Hong Kong on the afternoon of 22 August. Nuri crossed western Shenzhen and then made a second landfall near Nansha that night. It weakened first into a tropical storm on 23 August and a tropical depression that morning. Nuri weakened further into an area of low pressure over Guangdong subsequently.
A tropical depression formed over the western North Pacific about 470 km northeast of Manila on 27 August and moved generally northwestwards. The tropical depression skirted the northeastern tip of Luzon that evening and crossed the Luzon Strait the next day. It weakened into an area of low pressure over the Luzon Strait to the south of Taiwan on 29 August. Fig. 2.6 shows the satellite image of the tropical depression.
SEPTEMBER
Sinlaku (0813) formed as a tropical depression over the western North Pacific about 590 km east of Manila on 8 September and moved north-northwestwards. It intensified first into a tropical storm on 9 September, and further into a severe tropical storm and then a typhoon that day. Sinlaku moved northwards on 11 September but turned to move northwestwards on 12 September. It crossed the northern part of Taiwan on 14 September and weakened into a severe tropical storm that night. According to press reports, Sinlaku caused widespread flooding and landslides in Taiwan, collapsing bridges, tunnels and hotels. At least 11 people were killed and 11 missing, and the direct economic losses were around NT$0.7 billion. Sinlaku turned to move east-northeast over the East China Sea on 15 September and weakened into a tropical storm the next day. It intensified into a severe tropical storm again on 18 September and a typhoon the next day and skirted the southern coasts of Japan. Sinlaku weakened into a severe tropical storm on 20 September and a tropical storm the next day. It subsequently became an extra-tropical cyclone to the east of Japan.
Hagupit (0814) formed as a tropical depression over the western North Pacific about 1 720 km east of Manila on 19 September and moved west-southwestwards. It intensified first into a tropical storm on 20 September and moved west-northwestwards and then intensified into a severe tropical storm. Hagupit intensified further into a typhoon on 21 September and moved northwestwards. It turned to move west-northwestwards and crossed the Balintang Channel on 22 September and entered the South China Sea that evening. It crossed the northern part of the South China Sea the next day. Hagupit made landfall in western Guangdong on the morning of 24 September. It weakened into a severe tropical storm that afternoon and a tropical storm thereafter. Hagupit weakened into a tropical depression and further into an area of low pressure over northern Vietnam on 25 September.
Jangmi (0815) formed as a tropical depression over the western North Pacific about 260 km north of Yap on 24 September and moved west-northwestwards. It intensified into a tropical storm that evening and a severe tropical storm the next day. Jangmi intensified further into a typhoon on 26 September and moved northwestwards, and crossed northern Taiwan on the night of 28 September. Jangmi turned to move northwards and weakened into a severe tropical storm on 29 September. It weakened further to a tropical storm that evening and moved northeastwards. According to press reports, at least two people were killed, two missing and 61 injured in Taiwan. Electricity supply to about one million households was disrupted and the agricultural losses were estimated to be about NT$0.3 billion. A freighter sank in the waters of Wenzhou, one crewman was killed and five missing. Jangmi moved east-northeastwards across the East China Sea on 30 September and became an extra-tropical cyclone over the seas to the south-southwest of Japan on 1 October. Fig. 2.7 shows the satellite image of Jangmi.
Mekkhala (0816) formed as a tropical depression over the central part of the South China Sea about 270 km south of Xisha on 28 September and moved northwestwards. It intensified into a tropical storm on 29 September. Mekkhala turned to move west-northwestwards and made landfall over northern Vietnam on 30 September while weakening into a tropical depression. Mekkhala further weakened into an area of low pressure over Indochina on the early hours of 1 October. According to press reports, eight people were killed and eight others missing in Vietnam during the passage of Mekkhala. A fishing boat sank over the waters of Hainan Island but two crewmen on board were rescued.
Higos (0817) formed as a tropical depression over the western North Pacific about 900 km southeast of Manila on 30 September and moved northwestwards. It crossed the central part of the Philippines that afternoon and the next day and turned to move west-northwestwards, entering the central part of the South China Sea on the small hours of 2 October. Higos intensified into a tropical storm on the morning of 3 October and moved northwestwards. Higos turned to move northwards that night and made landfall near Wenchong in the eastern tip of Hainan. It weakened into a tropical depression on the early hours of 4 October and made landfall again near Wuchuan in western Guangdong that night. Higos weakened into an area of low pressure on the early hours of 5 October.
OCTOBER
A tropical depression formed to the south of Beibu Wan about 220 km north of Danang on 13 October and moved slowly north-northwestwards. It turned to move westwards the next evening and southwestwards on 15 October. It made landfall over northern Vietnam and weakened into an area of low pressure that evening.
Bavi (0818) formed as a tropical depression over the western North Pacific about 950 km east-southeast of Iwo Jima on 18 October and moved northwestwards initially. Bavi intensified into a tropical storm and moved north-northeastwards on the following afternoon. It finally became an extra-tropical cyclone over the western North Pacific to the east of Japan on 20 October.
NOVEMBER
Maysak (0819) formed as a tropical depression over the central part of the South China Sea about 540 km northeast of Nansha on the morning of 7 November. Moving west-northwestwards, it intensified into a tropical storm that evening. Maysak moved northwestwards on 8 November. It intensified into a severe tropical storm and turned to move north-northeastwards that evening. Under the influence of the northeast monsoon, Maysak turned to move southwards and weakened into a tropical storm on 9 November. It weakened into a tropical depression and subsequently an area of low pressure over the central part of the South China Sea on 10 November. Fig. 2.8 shows the satellite image of Maysak.
Haishen (0820) formed as a tropical depression about 640 km east of Iwo Jima on 15 November and moved northeastwards. It intensified into a tropical storm the next day and moved east-northeastwards. Haishen weakened first into a tropical depression on 17 November, and then became an extra-tropical cyclone over the western North Pacific to the east-southeast of Japan that day.
Noul (0821) formed as a tropical depression about 170 km east-southeast of Nansha on 16 November. Moving west-northwestwards, Noul intensified into a tropical storm that evening. Noul made landfall over southern Vietnam on 17 November and weakened into a tropical depression. It weakened into an area of low pressure over southern Vietnam the following day. Noul had reportedly resulted in some 15 deaths, two missing and eight others injured in Vietnam, over 100 fishing boats sank and over 8 000 hectares of crops damaged. Fig. 2.9 shows the satellite image of Noul.
DECEMBER
Note: Casualties and damage figures were compiled from press reports.
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