TROPICAL CYCLONES IN 2006
2.1 Review of tropical cyclones in 2006
| 2.1.1 | Tropical cyclones over the western North Pacific (including the South China Sea) |
In 2006, 27 tropical cyclones affected the western North Pacific and the South China Sea (i.e. the area bounded by the Equator, 45, 100 and 180° with one of them formed over the central part of the North Pacific and crossed the International Date Line into the western North Pacific. In the past 9 years (1998-2006), with the exception of 2004, the annual number of tropical cyclones in this ocean basin has been less than the 30-year (1961-1990) average of 31. Throughout the year, 14 tropical cyclones attained typhoon strength, two less than the normal figure.
The first tropical cyclone of the year formed in March. The monthly frequencies of the occurrence of tropical cyclones and typhoons in the western North Pacific and the South China Sea in 2006 are shown in Figure 2.1.
During the year, seven tropical cyclones hit mainland China, three affected Taiwan, four affected Japan (including Ryukyu Islands), one made landfall over South Korea, seven traversed the Philippines, another three made landfall over Vietnam.
The most intense tropical cyclone in 2006 was Saomai (0608). Saomai had a maximum wind speed of about 215 km/h and a minimum sea-level pressure of about 920 hPa when it was located over the sea to the northeast of Taiwan.
Cimaron (0619) was the tropical cyclone with the most peculiar track in 2006. After forming over the western North Pacific on 27 October, Cimaron generally took on a west-northwesterly course under the influence of the westerly steering current south of the upper subtropical ridge of high pressure. Following the weakening of the upper subtropical ridge over the South China Sea, Cimaron became almost stationary from 1 to 2 November. Thereafter, Cimaron turned south-southwestwards and dissipated over the South China Sea under the influence of the intense northeast monsoon.
2.1.2 Tropical cyclones in Hong Hong's area of responsibility
Amongst those 27 tropical cyclones in 2006, 16 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). Five of these 16 tropical cyclones developed within Hong Kong's area of responsibility. Altogether, 460 tropical cyclone warnings to ships and vessels were issued by the Hong Kong Observatory in 2006 (Table 4.2).
2.1.3 Tropical cyclones over the South China Sea
There were 13 tropical cyclones affecting the South China Sea (i.e. the area bounded by 10, 25, 105 and 120) in 2006. Four of them formed over the area. Nine moved into the area from the western North Pacific.
2.1.4 Tropical cyclones affecting Hong Kong
Seven tropical cyclones affected Hong Kong in 2006 (Figure 2.2), which is near normal (Table 2.2). These seven tropical cyclones were Chanchu (0601), Jelawat (0602), Prapiroon (0606), Bopha (0609), the tropical depressions in August and September and Cimaron (0619).
The highest signal issued this year was Strong Wind Signal No. 3 when Chanchu, Prapiroon and the tropical depression affected Hong Kong in May, August and September respectively.
Jelawat in June, Bopha and the tropical depression in August and Cimaron in October to November 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 2006 was 1 007.3 mm. This is 37% above the normal of 737.9 mm and accounts for some 38% of the year's total rainfall of 2 627.8 mm.
The tropical depression which affected Hong Kong on 12-13 September brought 265.6 mm of rainfall to Hong Kong, which was the tropical cyclone bringing the most rainfall to Hong Kong in 2006.
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 AND FEBRUARY
No tropical cyclone occurred over the western North Pacific and the South China Sea in January and February.
MARCH
A tropical depression formed about 510 km south of Yap on 4 March. Drifting slowly over the western North Pacific in the next two days, it turned to the west-southwest on 6 March and weakened into an area of low pressure the following day.
APRIL
No tropical cyclone occurred over the western North Pacific and the South China Sea in April.
MAY
Chanchu (0601) developed as a tropical depression over the western North Pacific about 420 km west-southwest of Yap on 9 May. Tracking mainly towards the west-northwest, it traversed the central Philippines. Chanchu entered the South China Sea and strengthened into a typhoon on 13 May. Moving westwards initially after entering South China Sea, Chanchu turned to the north and headed towards the south China coast on 15 May. The maximum sustained winds near the centre reached 185 km/h from 15 May to early 16 May, and it was the most intense tropical cyclone on record to have entered the South China Sea in May. It took on a north-northeastward course on 17 May and weakened gradually following landfall near Shantou the next morning. Chanchu rampaged through the coastal areas of southeastern China during the day on 18 May. That evening, it entered the East China Sea and became an extratropical cyclone.
JUNE
Jelawat (0602) developed as a tropical depression about 410 km east-southeast of Xisha Dao in the early morning of 27 June and moved generally northwest across the central part of the South China Sea. It intensified into a tropical storm that night. The next day, Jelawat skirted the northeastern coast of Hainan. It weakened into a tropical depression that night. Jelawat made landfall near Zhanjiang in the morning of 29 June and weakened further into an area of low pressure over the western part of Guangdong later that day.
Ewiniar (0603) formed as a tropical depression over the western North Pacific about 380 km south-southeast of Yap in the morning of 30 June. It moved generally towards the north-northwest and strengthened gradually to a typhoon on 3 July. Ewiniar traversed the Ryukyu Islands on 8 July and turned north afterwards, moving across the East China Sea. In the coastal areas of Zhejiang, more than 7 600 Ningbo residents were evacuated and over eight thousand fishing vessels returned to Ningbo and Zhoushan for shelter. In the morning of 10 July, Ewiniar weakened into a severe tropical storm. It then landed over the southwestern coast of South Korea and weakened further into a tropical storm. Ewiniar became an extratropical cyclone later that day. In Ewiniar's rage over South Korea, eight people were killed or reported missing and a dozen injured. More than 2 200 hectares of farmland were flooded and hundreds of schools were closed. In addition, 55 flights were cancelled and 30 000 vessels returned to shore to seek shelter.
JULY
Bilis (0604) formed as a tropical depression over the western North Pacific about 410 km northeast of Yap in the night of 8 July and moved generally towards the northwest. In the night of 11 July, Bilis strengthened into a severe tropical storm and skirted the eastern part of Luzon Strait the next day. Its outer circulation brought heavy rain and landslides to the northern part of the Philippines. In the fury of Bilis, 14 people were killed, another seven were reported missing and 20 000 people lost their homes. In the night of 13 July, Bilis skirted northern Taiwan. High winds and heavy rain led to three deaths and two people missing. Agricultural losses on the island exceeded NT$ 100 million. After traversing Taiwan Strait, Bilis made landfall over Fujian on 14 July. Moving inland, it weakened gradually and dissipated over Jiangxi the next day. Bilis inflicted severe damage to Fujian, Zhejiang, Hunan, Jiangxi, Guangdong and Guangxi. Altogether, 621 people were killed, another 208 were reported missing and 190 000 people were trapped by flood water. About 210 000 houses toppled, over 960 000 hectares of crops were affected and the direct economic losses exceeded RMB$ 24 billion.
Kaemi (0605) developed into a tropical depression over the western North Pacific about 380 km south of Guam on 18 July. It moved towards the west-northwest and intensified gradually, reaching typhoon strength on 21 July. Kaemi moved across southern Taiwan in the early morning of 25 July. During its passage, six people were injured and 475 evacuated. Power supply to 81 000 homes on the island was suspended and more than 40 flights were cancelled. Agricultural losses reached NT$ 77.38 million. Kaemi weakened into a severe tropical storm while traversing Taiwan Strait on the same day. It made landfall over Fujian that afternoon and continued to weaken afterwards. Kaemi finally dissipated over inland on 26 July. Kaemi brought severe damage to Anhui, Fujian, Jiangxi, Hunan and Guangdong. Altogether, 28 people were killed, another 36 were reported missing and 100 000 people were trapped by flood water. About 120 000 houses toppled, more than 480 000 hectares of crops were damaged and the direct economic losses exceeded RMB$ 1.1 billion.
Prapiroon (0606) developed as a tropical depression about 260 km northeast of Manila in the afternoon of 31 July and moved westwards across Luzon. After entering the South China Sea, Prapiroon turned west-northwest on 1 August. It strengthened into a typhoon the next day and headed towards the western coast of Guangdong. Prapiroon made landfall to the east of Zhanjiang in the night of 3 August and started to weaken afterwards. It dissipated over Guangxi the following night.
AUGUST
In the morning of 5 August, Maria (0607) formed as a tropical depression over the western North Pacific about 610 km east of Iwo Jima. It moved west-northwest and intensified into a severe tropical storm on 6 August. Maria turned northeast two days later and skirted the seas south of Honshu, Japan. It weakened into a tropical storm on 9 August and became an extratropical cyclone the following night. During Maria's passage over the seas south of Honshu, an aircraft heading for Tokyo encountered turbulence and five passengers on board were injured.
Saomai (0608) developed as a tropical depression over the western North Pacific about 380 km southeast of Guam in the morning of 5 August. It moved generally northwest and intensified into a typhoon in the afternoon of 7 August. Saomai then took a steady west-northwesterly track towards the coast of eastern China. It became the most intense tropical cyclone in 2006 with estimated maximum sustained winds of 215 km/h in the evening of 9 August and the morning of 10 August. Saomai made landfall over Zhejiang in the night of 10 August. Moving inland, Saomai started to weaken and dissipated over Jiangxi the next day. Saomai brought severe damage to Zhejiang, Fujian and Jiangxi. In these provinces altogether, at least 460 people were killed, 1 350 injured and another 50 reported missing. About two million people were evacuated, 60 000 houses toppled and the direct economic losses exceeded RMB$ 23.8 billion. In addition, one thousand fishing vessels were damaged in Fujian and the telecommunication system in coastal areas of Zhejiang was disrupted. More than 60 roads were closed in the two provinces.
Bopha (0609) developed as a tropical depression over the western North Pacific about 590 km southeast of Naha, Okinawa in the afternoon of 6 August and moved west-northwest. Bopha briefly attained the strength of a severe tropical storm during the day on 7 August. However, it weakened into a tropical storm that night and took a westerly track heading towards southern Taiwan. After skirting southern Taiwan, Bopha edged towards the coastal waters of eastern Guangdong. It weakened further into a tropical depression in the night of 9 August. Under the influence of Saomai, Bopha's movement was slow and erratic on 10 August. Bopha weakened into an area of low pressure that night.
A tropical depression named Wukong (0610) formed over the western North Pacific about 330 km south of Iwo Jima in the night of 12 August. While meandering towards the northwest, Wukong strengthened into a severe tropical storm on 15 August. Wukong weakened into a tropical storm two days later and made landfall over the southeast coast of Kyushu afterwards. After rampaging through Kyushu, Wukong became an extratropical cyclone in the night of 19 August. In the fury of Wukong, three people were killed, three injured and another one reported missing in Japan. About 110 people were evacuated and three houses were damaged. Electricity supply to about 200 families was suspended. In addition, 65 flights were cancelled.
Sonamu (0611) developed as a tropical depression over the western North Pacific about 980 km south of Naha, Okinawa in the early morning of 14 August and moved east-northeast. It strengthened into a tropical storm the same day. However, Sonamu started to weaken the following night and dissipated over the seas west of the Ogasawara Islands on 16 August.
A tropical depression developed over the northern part of the South China Sea about 210 km southeast of Haikou in the night of 23 August. It moved north initially but took a northeasterly track afterwards. The tropical depression turned northwest the following night, heading towards the western part of Guangdong. In the early morning of 25 August, the tropical depression made landfall near Yangjiang and weakened into an area of low pressure.
Having formed over the central part of the North Pacific, Typhoon Ioke (0612) crossed the International Date Line and entered the western North Pacific on 27 August. Ioke initially moved west-southwest, and turned west-northwest three days later. It turned northeast over the western North Pacific to the east of Japan on 5 September and weakened into a severe tropical storm in the morning of 6 September. Ioke became an extratropical cyclone that night.
SEPTEMBER
Shanshan (0613) developed as a tropical depression over the western North Pacific about 460 km north of Yap in the afternoon of 9 September, and moved northwest. It strengthened into a typhoon on 12 September and then took on a westerly track. Three days later, Shanshan turned north, skirting the seas east of Taiwan. Afterwards, Shanshan moved north-northeast and traversed northwestern Kyushu, Japan on 17 September. Shanshan weakened into a severe tropical storm on 18 September. It became an extratropical cyclone the following day. In the fury of Shanshan, nine people were killed in Japan, more than 280 injured and another one reported missing. About 12 000 people were evacuated. 40 houses were destroyed and another 190 damaged. Electricity supply to about 380 000 families was suspended. In addition, hundreds of flights were affected. A train was blown off the track and overturned. The southeastern part of South Korea was also affected by Shanshan. One person was injured and electricity supply to about 3 000 families was suspended. Ferry service between South Korea and Japan was suspended.
A tropical depression developed over the northern part of the South China Sea about 350 km east-northeast of Xisha in the afternoon of 12 September. It moved north initially but then took a west-northwesterly track. The tropical depression weakened into an area of low pressure over coastal waters of western Guangdong the following night.
Yagi (0614) developed as a tropical depression over the western North Pacific about 1450 km east-northeast of Guam in the early morning of 17 September and moved east slowly. Yagi turned west two days later and strengthened into a typhoon. Yagi took on a northwesterly track on 21 September. Two days later, it traversed the Ogasawara Islands and then turned northeast. Yagi weakened into a severe tropical storm on 24 September. It became an extratropical cyclone the next day.
A tropical depression developed over the central part of the South China Sea about 420 km south-southeast of Xisha in the night of 22 September and moved generally northwest. The tropical depression turned west on 24 September. It made landfall over the northern coast of Vietnam the next day and weakened into an area of low pressure.
Xangsane (0615) developed as a tropical depression over the western North Pacific about 900 km east-southeast of Manila in the night of 25 September and moved west-northwest. It strengthened into a typhoon two days later and rampaged through the Philippines. In the fury of Xangsane, over 207 people were killed in the Philippines, another 22 reported missing. Near two million people were made homeless, and another 43 million affected by power outage. Economic losses reached US$ 240 million. After entering the South China Sea, Xangsane took on a westerly track on 29 September towards the central part of Vietnam across the central part of the South China Sea. Xangsane made landfall over central Vietnam near Da Nang on 1 October. Moving inland, Xangsane weakened and finally dissipated in Thailand the next day. Xangsane inflicted severe damage to Vietnam. Altogether, 42 people were killed, thousands injured and another seven reported missing. 200 000 people were evacuated, 15 000 houses toppled and another 50 000 were flooded. In central Vietnam, electricity supply and telecommunication were disrupted. In addition, 48 flights were cancelled and 560 vessels sank or were damaged. Economic losses were about US$ 630 million. Hainan, China was also affected by Xangsane. One person was killed, 12 were injured and 200 made homeless. 70 houses were damaged and seven thousand trees were blown down. Economic losses were about US$ 800 000. In addition, ferry service across the Qiongzhou Haixia was suspended.
OCTOBER
Bebinca (0616) developed as a tropical depression over the western North Pacific about 1 270 km south-southeast of Naha, Okinawa early on 2 October, and moved slowly. Bebinca strengthened into a tropical storm the next day and accelerated to the north. It turned northeast on 4 October and became an extratropical cyclone two days later.
A tropical depression named Rumbia (0617) formed over the western North Pacific about 1 390 km east-southeast of Iwo Jima in the afternoon of 3 October. It moved north-northwest and strengthened into a tropical storm that night. Rumbia turned north on 5 October and dissipated over sea the next day.
Soulik (0618) developed as a tropical depression over the western North Pacific about 1 410 km east of Guam in the morning of 9 October and moved generally west-northwest. It strengthened into a typhoon on 12 October and turned north-northeast the next day, skirting the Ogasawara Islands. Soulik weakened into a severe tropical storm on 15 October and took on a northeasterly course. It became an extratropical cyclone the next day
Cimaron (0619) developed as a tropical depression over the western North Pacific about 1 390 km east of Manila early on 27 October and moved west. After strengthening into a tropical storm the same day, Cimaron took on a west-northwesterly track towards Luzon. Cimaron strengthened into a typhoon on 28 October and traversed Luzon the following night. Cimaron entered the South China Sea on 30 October and turned towards northwest the next day. It slowed down on 1 November and became almost stationary. Cimaron weakened into a severe tropical storm in the night of 2 November and took on a south-southwesterly course and continued to weaken. It dissipated over the central part of the South China Sea to the south-southeast of Xisha on 6 November.
NOVEMBER
Chebi (0620) developed as a tropical depression over the western North Pacific about 1 240 km east of Manila on 9 November and moved west. Chebi intensified into a tropical storm in the evening and then a severe tropical storm in the next morning. It further intensified into a typhoon in the afternoon of 10 November and traversed Luzon the next day. In the Philippines, 1 person was killed, eight injured and three others missing. Many villages were affected by floods and more than 8 000 people were evacuated from their homes. After entering the South China Sea, Chebi turned to a west-southwest track and weakened into a severe tropical storm in the evening of 12 November. It then turned to a northwesterly track on 13 November and weakened to a tropical storm in the afternoon. Chebi continued to weaken to a tropical depression in the morning of 14 November and dissipated over the sea to the southeast of Hainan in the evening.
Durian (0621) developed as a tropical depression over the western North Pacific about 830 km east of Yap on 26 November and moved generally west-northwest. It intensified into a tropical storm in the afternoon. Durian intensified into a severe tropical storm on 28 November and further into a typhoon the next day. While moving west, it crossed the central part of the Philippines on 30 November. Heavy rain associated with Durian triggered widespread mudslides in the region. Over 570 people were killed and 746 missing. In addition, up to 120 000 houses were destroyed and over one million people affected. Power, communications and water supply were interrupted in the region. The damage to crops was estimated to be as high as US$10 million. Typhoon Durian entered the central part of the South China Sea on 1 December on a westerly track. It changed to a west-southwesterly track on 3 December and then a southwesterly track the next day. Durian weakened into a severe tropical storm in the afternoon of 4 December and further into a tropical storm in the morning of 5 December, skirting the coasts of the southern part of Vietnam. Durian brought heavy rain and high winds to the southern part of Vietnam. 67 people were killed, 31 others missing and more than 450 people were injured. More than 120 000 homes were destroyed and over 1 000 fishing boats sank. In addition, power and communication lines were severely damaged and many trees were uprooted. Durian weakened into a tropical depression in the afternoon of 5 December and dissipated over the coastal areas of the southern part of Vietnam later in the afternoon.
DECEMBER
Utor (0622) developed as a tropical depression over the western North Pacific about 1 800 km east-southeast of Manila on 7 December. Moving west-northwestwards, Utor intensified into a tropical storm in the early morning and then a severe tropical storm in the evening of 8 December. It further intensified into a typhoon at noon the next day and started crossing the central Philippines in the afternoon. In the Philippines, at least seven were killed, 15 people missing and over 90 000 people were evacuated. Utor knocked out utilities and power lines, damaged resorts and houses, and caused severe flooding and several mudslides. Utor entered the South China Sea in the afternoon of 10 December and continued to move west-northwestwards. It turned to a northwesterly track on 12 December and then slowed down the next day as it turned to move northwards. Under the influence of the northeast monsoon, Utor weakened rapidly on 14 December and turned to move east-northeastwards. It first weakened into a tropical storm in the morning, then weakened further into a tropical depression in the afternoon. It dissipated over the South China Sea to the northeast of Xisha at night.
Trami (0623) developed as a tropical depression over the western North Pacific about 310 km northeast of Yap on 17 December and moved northwestwards. It intensified into a tropical storm in the early morning of 18 December and then turned on a west-northwesterly track. Trami weakened into a tropical depression in the morning of 19 December and dissipated over the western North Pacific to the east of Luzon in the afternoon.
Note: Casualties and damage figures were compiled from press reports.
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