TROPICAL CYCLONES IN 2005

2.1 Review of tropical cyclones in 2005

In 2005, 26 tropical cyclones occurred over the western North Pacific and the South China Sea (i.e. the area bounded by the Equator, 45, 100 and 180°, less than the 30-year (1961-1990) average of 31. Throughout the year, 13 tropical cyclones attained typhoon strength, three less than the normal figure.

The first tropical cyclone of the year formed in January. The monthly frequencies of the occurrence of tropical cyclones and typhoons in the western North Pacific and the South China Sea in 2005 are shown in Figure 2.1.

During the year, eight tropical cyclones hit mainland China, three affected Taiwan, three affected Japan (including Ryukyu Islands), four traversed the Philippines, another six made landfall over Vietnam.

The most intense tropical cyclone in 2005 was Nabi (0514). Nabi had a maximum wind speed of about 220 km/h and a minimum sea-level pressure about 910 hPa.

2.1.2 Tropical cyclones in Hong Hong's area of responsibility

Amongst those 26 tropical cyclones in 2005, 15 occurred inside Hong Kong's area of responsibility (i.e. the area bounded by 10, 30, 105 and 125). This was near the 30-year (1961-1990) annual average of 16.4 (Table 2.1). Six of these 15 tropical cyclones developed within Hong Kong's area of responsibility. Altogether, 301 tropical cyclone warnings to ships and vessels were issued by the Hong Kong Observatory in 2005 (Table 4.2).

2.1.3 Tropical cyclones over the South China Sea

There were 11 tropical cyclones affecting the South China Sea (i.e. the area bounded by 10, 25, 105 and 120) in 2005. Five of them formed over the area. Six moved into the area from the western North Pacific.

2.1.4 Tropical cyclones affecting Hong Kong

Only three tropical cyclones affected Hong Kong in 2005 (Figure 2.2), three less than the normal number (Table 2.2). These three tropical cyclones were Sanvu (0510), Vicente (0516) and Damrey (0518).

The highest signal issued this year was Strong Wind Signal No.3 when Damrey affected Hong Kong in September. Sanvu in August and Vicente in September only necessitated the issuance of the Standby Signal No. 1 in Hong Kong.

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 2005 was 584.0 mm. This is 21 % below the normal of 737.9 mm and accounts for some 18 % of the year's total rainfall of 3214.5 mm.

2.2 Monthly overview

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

Kulap (0501) formed as a tropical depression over the western North Pacific about 850 km south-southeast of Guam on 14 January and headed north. After intensifying into a tropical storm the following day, Kulap traversed the seas east of Guam and turned northeastwards on 16 January. It further intensified into a severe tropical storm on 18 January. Kulap weakened into a tropical storm early next morning before degenerating into an area of low pressure over the western North Pacific.

FEBRUARY

No tropical cyclone occurred over the western North Pacific and the South China Sea in February.

MARCH

Roke (0502) formed as a tropical depression over the western North Pacific about 590 km south of Guam on 13 March and headed west-northwestwards. It turned west on 15 March and intensified into a severe tropical storm the next day. Roke swept across the central part of the Philippines on 17 March and weakened gradually. It dissipated over the South China Sea the following day. Under the influence of Roke, at least eight people were killed and one reported missing in the Philippines. In addition, a ferry and a fishing boat capsized.

APRIL

Sonca (0503) formed as a tropical depression over the western North Pacific about 340 km northwest of Yap on 22 April and moved westwards. After intensifying into a tropical storm in the following day, it took on a northwesterly course. Sonca strengthened rapidly into a typhoon on 24 April. It turned to the northeast the next day. On 27 April, it became an extratropical cyclone after skirting the sea areas north of Iwo Jima.

MAY - JUNE

Nesat (0504) formed as a tropical depression about 430 km south-southeast of Guam on 31 May. Moving west-northwestwards, it reached typhoon strength in the early morning of 2 June. Nesat began to track northwestwards the next day and turned northeastwards on 5 June. It weakened gradually on 9 June over the sea areas to the south of Japan and became an extratropical cyclone over the Pacific two days later.

JULY

Haitang (0505) developed as a tropical depression about 1170 km east of Iwo Jima on 11 July. Tracking generally towards the west-southwest, it intensified into a typhoon over the seas to the north of Mariana Islands on 14 July. Haitang turned west-northwest the following day and made landfall over the eastern coast of Taiwan on 18 July. In the fury of Haitang, six people were killed, 30 injured, one reported missing, and the electricity supply of over one million households were interrupted in Taiwan. The economic loss exceeded NT$ 0.45 billion. After moving across the Taiwan Strait on 19 July, Haitang made landfall over the coast of Fujian and weakened into a severe tropical storm that night. Under the influence of Haitang, at least three people were killed and over one million people had to be evacuated in Fujian and Zhejiang. Haitang moved further inland and dissipated the next day.

A tropical depression named Nalgae (0506) formed over the Pacific about 610 km north-northwest of Wake Island on 20 July. Moving northwestwards, Nalgae strengthened into a tropical storm that day. It adopted a generally northeastward course on 22 July. Nalgae dissipated over the Pacific on 24 July.

On 21 July, Banyan (0507) developed as a tropical depression over the Pacific about 480 km north of Yap. Tracking northwards, Banyan attained severe tropical storm strength on 23 July. It turned to the northeast on 26 July. After skirting the southeastern coast of Honshu of Japan, Banyan became an extratropical cyclone on 28 July. Under the influence of Banyan, at least 43 flights were cancelled in Japan.

Washi (0508) developed as a tropical depression over the South China Sea about 320 km southwest of Dongsha on 28 July. Moving west-northwestwards, it strengthened into a tropical storm on 29 July. Washi swept across Hainan the following day. It made landfall over the coast of northern Vietnam on 31 July and dissipated over northern Laos early next morning. In the last three days of the month, the rain bands associated with Washi brought occasional heavy showers and squally thunderstorms to Hong Kong.

Tropical depression Matsa (0509) developed over the Pacific about 260 km northwest of Yap on 31 July. While tracking towards the northwest, Matsa intensified into a typhoon on 2 August. In the next 2 days, it moved across the sea areas east of Taiwan. Torrential rain associated with Matsa triggered a number of landslides and floods in Taiwan, injuring at least seven people. Another two persons were reported missing. Agricultural losses were estimated at around NT$ 40 million. Matsa made landfall over Zhejiang on 6 August and dissipated over Shandong on 8 August. In the fury of Matsa, at least eight people were killed in eastern China. The economic loss exceeded RMB 6 billion.

AUGUST

Sanvu (0510) developed as a tropical depression about 990 km east of Manila on 10 August and moved towards the west-northwest. After traversing the Luzon Strait, it intensified into a severe tropical storm over the northern part of the South China Sea on the night of 12 August. Sanvu made landfall near Shantou in Guangdong and became a tropical storm the following day. On 14 August, Sanvu weakened further and dissipated over inland.

A tropical depression named Mawar (0511) formed over the Pacific about 470 km south-southeast of Iwo Jima on 20 August. Tracking northwestwards, it attained typhoon strength on 21 August. Mawar adopted a northward course towards Japan two days later and turned to the northeast on 25 August. Mawar weakened into a tropical storm the next day after skirting the southeastern coast of Honshu in Japan. It became an extratropical cyclone over the Pacific in the morning of 27 August. Under the influence of Mawar, one person was killed and another five injured in Japan. At least 30 flights were cancelled.

On 21 August, Guchol (0512) developed as a tropical depression about 880 km east-southeast of Iwo Jima and moved towards the north-northwest. It intensified into a severe tropical storm the next day. Guchol turned to the northeast on 23 August and became an extratropical cyclone over the Pacific on 25 August.

Talim (0513) developed as a tropical depression over the Pacific about 150 km south-southwest of Guam on 26 August. Tracking northwestwards, it reached typhoon strength on 28 August. Talim then adopted a west-northwestward track and swept across Taiwan in the morning of 1 September. During the passage of Talim, at least seven people were found dead and 200 others were hurt in Taiwan. Agricultural losses were estimated at NT$ 1.2 billion. Talim made landfall over Fujian and moved inland that afternoon. It degenerated into an area of low pressure the next day. Talim inflicted severe damage in several provinces, killing 96 people. Some 30 people were reported missing. The economic loss exceeded RMB 12 billion.

A tropical depression named Nabi (0514) formed about 940 km east of Guam on 29 August and moved westwards. It intensified into a typhoon in the early morning of 31 August and traversed Mariana Islands the same day. Nabi then tracked in the general direction towards Kyushu in the next few days. It made landfall near Kagoshima on 6 September. Nabi then turned to the northeast and weakened into a severe tropical storm over the Sea of Japan the following day. After traversing Hokkaido, it became an extratropical cyclone in the morning of 8 September. In the fury of Nabi, 21 people were killed, 149 injured, another six reported missing in Japan. Near 2000 houses were destroyed and power supply to about 270000 families was suspended.

SEPTEMBER

Khanun (0515) developed as a tropical depression about 100 km north of Yap on 6 September. Moving northwestwards, it attained typhoon strength on 9 September. Khanun made landfall over Zhejiang on 11 September and moved across Jiangsu in the following day. It eventually dissipated over the Yellow Sea in the early morning of 13 September. During its passage, at least 14 persons were killed, and another nine were reported missing in eastern China.

On 12 September, a tropical depression formed over the South China Sea, about 370 km south-southeast of Xisha Dao. It took on a westward course and dissipated over coastal areas of southern Vietnam the next morning.

On 16 September, Vicente (0516) formed as a tropical depression over the South China Sea about 80 km northwest of Nansha Dao. Moving generally towards the north, it deepened into a tropical storm that evening. Vicente turned west-northwestwards on 17 September and made landfall over Vietnam the following day. On 19 September, it degenerated into an area of low pressure over the northern part of Laos.

A tropical depression named Saola (0517) formed about 1120 km east-southeast of Iwo Jima on 20 September. Moving towards the west-northwest, it intensified into a typhoon on 22 September and then traversed the sea between Iwo Jima and Ogasawara Islands. Saola turned northeastwards on 24 September over the Pacific to the south of Japan. It weakened into a severe tropical storm and subsequently became an extratropical cyclone over the seas east of Japan two days later.

Damrey (0518) developed as a tropical depression over the Pacific about 310 km east-northeast of Baguio in the early morning of 21 September. It moved northwestwards and intensified into a tropical storm before skirting the northeastern tip of Luzon that morning. Over the South China Sea, Damrey turned to the west the following day and then tracked in the general direction of Hainan. It gradually intensified into a typhoon while moving across the northern part of the South China Sea. Damrey swept across Hainan on 26 September and made landfall over northern Vietnam the next day. It eventually dissipated over Laos on 28 September.

A tropical depression named Longwang (0519) formed about 620 km south-southeast of Iwo Jima on 26 September. Tracking generally west-northwest, it reached typhoon strength on 27 September. Longwang swept across Taiwan in the morning of 2 October, causing one death and injuring some 50 people. Another person was reported missing. Power supply to some 760000 households was interrupted. Agricultural losses exceeded NT$ 100 million. Longwang made landfall near Xiamen in the evening of 2 October and dissipated over inland area the next day. It also inflicted severe damage in Fujian where at least 60 people died, some 20 others were reported missing, and about 540000 people had to be evacuated. In addition, around 5400 houses were damaged. The economic loss exceeded RMB 1.2 billion.

OCTOBER

On 7 October, a tropical depression formed over the South China Sea about 120 km east-northeast of Da Nang and moved westwards. It dissipated soon after crossing central Vietnam early next morning.

Kirogi (0520) developed as a tropical depression about 720 km west-southwest of Iwo Jima on 10 October and moved generally southwestwards. It intensified into a typhoon the next day and then headed slowly towards the north-northwest. Kirogi changed direction again on 15 October and began to track northeastwards. Traversing the seas between Honshu and Ogasawara Islands, Kirogi weakened into a tropical storm in the early morning of 19 October and became an extratropical cyclone later that day.

Kai-tak (0521) formed as a tropical depression over the South China Sea about 280 km north of Nansha Dao on 28 October. Moving generally towards the northwest, it attained typhoon strength on 30 October. Kai-tak made landfall over Vietnam on 2 November and dissipated near Ha Noi that evening. During its passage, some 20 people were killed and 14 injured in Vietnam. Near 7500 houses were damaged.

NOVEMBER

Tembin (0522) developed as a tropical depression over the Pacific about 250 km north of Yap on 7 November. Tracking mainly towards the west-northwest, it intensified into a tropical storm in the morning of 10 November. Tembin made landfall over the eastern coast of Luzon that evening and dissipated over the South China Sea the next day.

A tropical depression named Bolaven (0523) formed about 960 km southeast of Manila on 14 November. Meandering towards the north in the following days, Bolaven intensified into a severe tropical storm on 17 November. It took on the west-northwestward course on 18 November and turned to the northwest the next day. Bolaven weakened gradually thereafter and dissipated over seas east of Luzon on 20 November.

DECEMBER

A tropical depression formed about 340 km west-southwest of Nansha Dao on 19 December and tracked generally northwest. It turned to the southwest the next morning and dissipated over the seas off southern Vietnam that afternoon.

Note: Casualties and damage figures were compiled from press reports.

- Top -