TROPICAL CYCLONES IN 2013

2.1 Review of tropical cyclones in 2013

2.1.1 Tropical cyclones over the western North Pacific (including the South China Sea)

In 2013, a total of 33 tropical cyclones occurred over the western North Pacific and the South China Sea bounded by the Equator, 45°N, 100°E and 180°, slightly more than the long term (1961-2010) average figure of around 30.  During the year, 14 of the tropical cyclones attained typhoon intensity or above, close to the long term average (15) of 1961 – 2010.  Seven of them reached super typhoon intensity (maximum 10-minute wind speed of 185 km/h or above near the centre), the highest since 2006.

The first tropical cyclone of the year formed in January and the last one in November.  Figure 2.1 shows the monthly frequencies of the occurrence of tropical cyclones in the western North Pacific and the South China Sea in 2013.

During the year, nine tropical cyclones made landfall over mainland China, with one of them making landfall over the south China coast within 300 km of Hong Kong.  One tropical cyclone crossed Taiwan, two made landfall over Japan, seven traversed the Philippines and nine made landfall over Vietnam.

The most intense tropical cyclone in 2013 over the western North Pacific and the South China Sea was Super Typhoon Haiyan (1330) in November (Figures 2.3) with an estimated maximum sustained wind speed of 285 km/h and a minimum sea-level pressure of 885 hPa near its centre (Table 4.1).  Haiyan was also the most intense tropical cyclone in the region since Super Typhoon Tip in October 1979.

2.1.2 Tropical cyclones in Hong Kong’s area of responsibility

Amongst the 33 tropical cyclones in 2013, 19 of them occurred inside Hong Kong’s area of responsibility (i.e. the area bounded by 10°N, 30°N, 105°E and 125°E), more than the long term annual average figure of around 16 by three (Table 2.1).  Nine of them developed within Hong Kong’s area of responsibility.  Altogether, 444 tropical cyclone warnings to ships and vessels were issued by the Hong Kong Observatory in 2013 (Table 4.2).

2.1.3 Tropical cyclones over the South China Sea

14 tropical cyclones affected the South China Sea bounded by 10°N, 25°N, 105°E and 120°E in 2013, more than the long term annual average of around 12.  Seven of them formed over the area while the other seven moved into the area from the western North Pacific or from the sea areas to the south.

2.1.4 Tropical cyclones affecting Hong Kong

In 2013, the typhoon season in Hong Kong started on 21 June when Tropical Depression Bebinca (1305) over the northern part of the South China Sea turned to move northwestwards, necessitating the issuance of the Standby Signal No. 1.  The typhoon season ended on 3 November when Tropical Storm Krosa (1329) moved southwestwards away from Hong Kong and all tropical cyclone warning signals were cancelled.

Seven tropical cyclones affected Hong Kong during 2013 (Figure 2.2), slightly more than the long term (1961-2010) average figure of about six in a year (Table 2.2).  These seven tropical cyclones were Tropical Storm Bebinca (1305) and Severe Tropical Storm Rumbia (1306) in June, Tropical Storm Cimaron (1308) and Severe Tropical Storm Jebi (1309) in July, Super Typhoon Utor (1311) in August, Super Typhoon Usagi (1319) in September and Severe Typhoon Krosa (1329) in October.  The No. 8 Gale or Storm Signal was issued during the passages of Utor and Usagi, the highest tropical cyclone warning signal in 2013.  The Strong Wind Signal No. 3 was issued during the passages of Bebinca, Rumbia and Jebi.  Cimaron and Krosa only necessitated the issuance of Standby Signal No. 1 in Hong Kong.

2.1.5 Tropical cyclone rainfall

Tropical cyclone rainfall (total rainfall recorded at the Hong Kong Observatory from the time when a tropical cyclone comes within 600 km of Hong Kong to 72 hours after it has dissipated or moved more than 600 km away from Hong Kong) in 2013 was 645.4 mm (Table 4.8.1).  This accounted for approximately 23 % of the year’s total rainfall of 2847.3 mm and was about 5 % below the 1981-2010 average of 678.0 mm.

Super Typhoon Utor (1311) brought 154.1 mm of rainfall to the Hong Kong Observatory Headquarters (Table 4.8.1) and was the wettest tropical cyclone in 2013.

2.2 Monthly overview

A monthly overview of tropical cyclones is given in this section.  Detailed reports on tropical cyclones affecting Hong Kong, including reports of damage, are presented in Section 3.

Mangkhut (1310) formed as a tropical depression over the central part of the South China Sea about 790 km southeast of Xisha on 5 August and moved to the west-northwest or northwest, intensifying into a tropical storm southwest of Xisha the next day. It reached its peak intensity with estimated sustained winds of 75 km/h and skirted the southwestern coast of Hainan on 7 August, making landfall over the coast of northern Vietnam that night. Mangkhut dissipated over the northern part of Laos the next day. According to press reports, at least three people were killed, 14 houses collapsed and over 700 houses damaged in Vietnam during the passage of Mangkhut.

Utor (1311) formed as a tropical depression over the western North Pacific about 1 350 km east of Manila on 9 August and moved westwards initially. It took on a west-northwesterly track and gradually became a typhoon the next day. Utor continued to strengthen on 11 August and became a super typhoon about 290 km east-northeast of Manila in the evening, reaching its peak intensity with estimated sustained winds of 195 km/h near its centre. It crossed Luzon and weakened into a severe typhoon in the small hours on 12 August, entering the South China Sea in the morning and turning to move northwestwards over the northern part of the South China Sea to the south of Hong Kong the next day. It weakened into a typhoon and made landfall near Yangjiang in the afternoon on 14 August, moving across the coast of western Guangdong in the evening and weakening into a severe tropical storm that night. Utor took on a northerly track across Guangxi and weakened gradually into a tropical depression the next day. It finally dissipated over the inland areas of Guangxi on 16 August.

Trami (1312) formed as a tropical depression over the sea areas about 550 km east-southeast of Gaoxiong, Taiwan on 17 August and moved east-southeastwards slowly in general. It gradually intensified into a severe tropical storm over the next couple of days. Trami turned to move northwestwards on 20 August. It intensified further into a typhoon the next day, reaching peak intensity with estimated sustained winds of 120 km/h near its centre, crossing the sea areas north of Taiwan at night. Trami made landfall over the coast of Fujian in the small hours of 22 August and gradually weakened into a tropical storm during the day, dissipating over Hunan the next day. Trami caused flooding in Taiwan during its passage, where three people were killed and 11 others injured. Trami also brought rainstorms to Fujian, Shantou and Hunan, where at least eight people were killed, six people missing and over 30 people injured. Moreover, more than 300 fishing boats sank in Fujian during the passage of Trami, with a direct economic loss of around 2.1 billion RMB reported.

Having formed over the central part of the North Pacific, Severe Tropical Storm Pewa (1313) crossed the International Date Line and entered the western North Pacific on a northwesterly track on 18 August. Pewa reached its peak intensity with estimated sustained winds of 110 km/h near its centre the next day. It weakened into a tropical storm to the east-southeast of Wake Island and took on a west-northwesterly track on 20 August. Pewa turned to track northwestwards on 22 August and became slow-moving the following day, and finally dissipated over the western North Pacific to the north of Wake Island on 24 August.

Also coming from the central part of the North Pacific, Tropical depression Unala (1314) crossed the International Date Line and entered the western North Pacific on 19 August, with estimated sustained winds of 55 km/h near its centre. Unala moved westwards and dissipated over the sea that night.

Kong-rey (1315) formed as a tropical depression over the western North Pacific about 610 km east-northeast of Manila on 26 August. Moving generally northwestwards, it intensified into a tropical storm that night. It turned northwards the next day, and intensified into a severe tropical storm while taking a northerly track across the seas east of Taiwan on 28 August. It reached peak intensity with estimated sustained winds of 105 km/h near its centre the next day, before soon weakening into a tropical storm in the evening. Kong-rey turned to move northeastwards over the East China Sea on 30 August and became an extratropical cyclone that night. In Taiwan, one fisherman was reported missing during the passage of Kong-rey.

Yutu (1316) formed as a tropical depression over the western North Pacific about 1 380 km north-northeast of Wake Island on 31 August and moved northeastwards slowly. It reached peak intensity with estimated sustained winds of 55 km/h near its centre that night. Yutu remained slow-moving in the following days and dissipated over the sea on 3 September.

Toraji (1317) formed as a tropical depression over the sea areas about 240 km east-northeast of Taibei on 1 September and moved generally northeastwards. It intensified into a tropical storm west of Okinawa the next day. Toraji reached its peak intensity with estimated sustained winds of 85 km/h near its centre on 3 September. It made landfall over southern Kyushu, Japan on 4 September and gradually evolved into an extratropical cyclone. According to press reports, around 7000 people in western Japan were advised to evacuate from their homes due to flooding caused by Toraji.

Man-yi (1318) formed as tropical depression over the western North Pacific about 960 km north of Guam on 12 September and moved west to west-northwestwards. It intensified into a tropical storm the next day. Moving along a north-northwesterly track on 14 September, it intensified further into a severe tropical storm. Man-yi turned to take a north-northeasterly track over the seas south of Japan, reaching peak intensity with estimated sustained winds of 105 km/h near its centre. Man-yi made landfall over southern Honshu, Japan on the morning of 16 September and weakened gradually, before evolving into an extratropical cyclone over the seas east of Japan that evening. Man-yi brought heavy rain and flooding to widespread areas of Japan, where at least three people were killed, four were reported missing and over 100 people were injured. Electricity supply to over 17000 households was disrupted.

Usagi (1319) formed as a tropical depression over the western North Pacific about 1240 km east-northeast of Manila on 17 September. Moving generally westwards, it gradually intensified and became a typhoon the next day. Usagi took on a northwesterly track and intensified further into a super typhoon over the Pacific to the east of Luzon on 19 September, reaching peak intensity with estimated sustained winds of 205 km/h near its centre the next day. Moving west-northwestwards, Usagi crossed the Luzon Strait on 21 September and entered the South China Sea, weakening into a severe typhoon. It moved across the northeastern part of the South China Sea on 22 September, made landfall near Shanwei, Guangdong that evening and moved across the coastal areas of Guangdong during the night. Usagi dissipated over the inland region of Guangxi the following day.

A tropical depression formed over the central part of the South China Sea about 320 km east of Danang on 18 September and moved west to west-northwestwards across the seas south of Hainan Island. The estimated maximum sustained winds near its centre was about 55 km/h. The tropical depression dissipated over land after making landfall over the central part of Vietnam the following day.

Pabuk (1320) formed as a tropical depression over the western north Pacific about 700 km north-northeast of Guam on 21 September and moved generally west to west-northwestwards, and intensified into a tropical storm in the afternoon. It continued to intensify into a severe tropical storm on 22 September and became a typhoon near Iwo Jima two days later, reaching peak intensity with estimated sustained winds of 140 km/h near its centre. Pabuk turned to move northeastwards over the Pacific to the south of Japan on 25 September and became an extratropical cyclone to the east of Japan the following day.

Wutip (1321) formed as a tropical depression over the central part of the South China Sea about 620 km east-southeast of Xisha on 26 September and moved generally northwestwards. It intensified into a tropical storm the following day. Wutip moved slowly across the seas east of Xisha and intensified into a severe tropical storm on 28 September. It took a westerly track and passed to the south of Xisha on 29 September and intensified gradually into a severe typhoon, reaching peak intensity with estimated sustained winds of 155 km/h near its centre. Wutip weakened into a typhoon in the small hours of the following day. It made landfall over the coast of central Vietnam on 30 September and weakened into a severe tropical storm. Wutip dissipated near the border between Laos and Thailand on 1 October. Three fishing boats sank over the waters near Xisha during the passage of Wutip. Four fishermen were killed and 58 others were reported missing. In Vietnam, three people were killed, 35 people were injured and 95000 houses were destroyed.

Sepat (1322) formed as a tropical depression over the western North Pacific about 710 km east-northeast of Iwo Jima on 30 September and moved west to west-northwestwards. It intensified into a tropical storm that afternoon and reached its peak intensity with estimated sustained winds of 75 km/h near its centre at night. Sepat turned to move north to north-northeastwards on the afternoon of 1 October, skirting the seas off southeastern Japan the following day. It evolved into an extratropical cyclone on 3 October.

Fitow (1323) formed as a tropical depression over the western North Pacific about 1 250 km east of Manila on 30 September and moved generally north-northwestwards. It intensified gradually into a typhoon over the next three days. Fitow turned to move west-northwestwards near Ryukyu Islands on 5 October and intensified into a severe typhoon, reaching peak intensity with estimated sustained winds of 155 km/h near its centre. It crossed the seas north of Taiwan the following day and weakened into a typhoon. After making landfall over the coast of Fujian in the small hours on 7 October, Fitow weakened rapidly and dissipated inland that evening. According to press reports, five people were killed, four others were missing, around 2 300 houses collapsed and 180 000 hectares of farmland were inundated in Fujian during the passage of Fitow with direct economic loss exceeding 4.7 billion RMB.

Danas (1324) formed as a tropical depression over the western North Pacific about 350 km north-northeast of Guam on 4 October. Moving west-northwestwards, Danas intensified gradually and became a typhoon on 6 October. It intensified further into a super typhoon east-southeast of Okinawa the following day, reaching its peak intensity with estimated sustained winds of 195 km/h near its centre and passing to the northeast of Okinawa on a northwesterly track. It turned gradually northeastwards across the seas west of Japan on 8 October and weakened gradually into a severe tropical storm. Danas became an extratropical cyclone over the Sea of Japan the next day. During the passage of Danas, flooding was reported in Jeju and parts of southern Korea and electricity supply was interrupted.

Nari (1325) formed as a tropical depression over the western North Pacific about 990 km east of Manila on 9 October and moved west to west-northwestwards. It gradually intensified and became a typhoon to the east of Luzon on 11 October, reaching peak intensity with estimated sustained winds of 145 km/h near its centre. Nari swept past Luzon that night and tracked across the central part of the South China Sea over the next three days, passing to the south of Xisha. It made landfall over the coast of central Vietnam on 15 October, weakening gradually into a tropical depression and dissipating over Laos that night. In the Philippines, 13 people were killed and more than two million people were left without electricity supply during the passage of Nari. In Vietnam, five people were killed and 49 people were injured.

Wipha (1326) formed as a tropical depression over the western North Pacific about 200 km west of Guam on 10 October. It gradually intensified into a severe tropical storm and took on a northwesterly track the following day. Wipha intensified into a severe typhoon to the south-southwest of Iwo Jima on 13 October, reaching peak intensity the following day with estimated sustained winds of 175 km/h near its centre. It turned northeastwards across the seas south of Japan on 15 October and weakened into a typhoon. After crossing the coastal waters of eastern Japan the next day, Wipha became an extratropical cyclone. Wipha brought flash floods and triggered landslides in eastern Japan, where at least 17 people were killed, 51 people were missing and 20 people were injured. Around 300 houses collapsed or were damaged, and over 30000 households were left without electricity.

Francisco (1327) formed as a tropical depression over the western North Pacific about 230 km east of Guam on 16 October and moved west-southwestwards initially. Francisco intensified into a typhoon the following day and turned to move north-northwestwards. It intensified further into a super typhoon on 18 October, reaching peak intensity the following day with estimated sustained winds of 230 km/h near its centre. Francisco weakened into a severe typhoon on 21 October and further into a typhoon two days later. It turned to move northwards across the seas east of Okinawa on 24 October. Francisco weakened into a severe tropical storm on 25 October and moved northeastwards across the seas south of Japan. It evolved into an extratropical cyclone over the Pacific southeast of Japan the following day.

Lekima (1328) formed as a tropical depression over the western North Pacific about 1190 km south-southwest of Wake Island on 20 October and moved generally north-northeastwards initially. Lekima gradually intensified over the Pacific and moved on a northwesterly track, becoming a typhoon in the morning on 22 October and a super typhoon about 1200 km east-northeast of Guam that evening. It reached its peak intensity with estimated sustained winds of 220 km/h near its centre the following day. Passing to the east of Iwo Jima on 25 October, Lekima gradually took on a northeasterly track and weakened into a typhoon the next day before becoming an extratropical cyclone over the Pacific east of Japan.

Krosa (1329) formed as a tropical depression over the western North Pacific about 1580 km east of Manila on 29 October. Moving generally west to west-northwestwards, it intensified gradually into a severe tropical storm the following day. Krosa intensified further into a typhoon on 31 October and crossed the northern tip of Luzon. Krosa entered the northern part of the South China Sea on 1 November. It became slow moving and intensified into a severe typhoon over the northern part of the South China Sea on 2 November, reaching its peak intensity with estimated sustained winds of 165 km/h near its centre. Krosa turned southwestwards on 3 November and weakened gradually into a tropical storm, dissipating over the central part of the South China Sea during the following night. According to press reports, three people were killed, two people were missing and more than 17000 houses were damaged in the Philippines during the passage of Krosa.

Haiyan (1330) formed as a tropical depression over the western North Pacific about 1600 km east-southeast of Guam on 3 November and moved west-northwestwards. Haiyan intensified gradually and became a typhoon about 780 km south-southwest of Guam two days later. It strengthened further into a super typhoon on 6 November, reaching its peak intensity with estimated sustained winds of 285 km/h near its centre on 8 November, with its eye clearly discernible on satellite images. Haiyan moved across the central Philippines and entered the South China Sea on 9 November. Turning northwestwards, it passed to the southwest of Xisha and weakened into a severe typhoon at night. It moved across Beibu Wan the following day and weakened into a typhoon. Haiyan made landfall over the coast of northern Vietnam on 11 November, weakened rapidly into a tropical depression and turned east-northeastwards. It dissipated over Guangxi the following day.

According to press reports, Haiyan caused widespread flooding in the central Philippines and brought hugh waves to coastal regions, resulting in landslides, collapsed houses, uprooted trees, power failure and disruption in sea and air traffic. Over 6 000 people were killed, around 1800 people were reported missing, 28 000 people were injured and the direct economic loss exceeded 10.3 billion Pesos (around HK$1.9 billion) in the Philippines. In Hainan Island, Guangxi and Guangdong, seven people were killed, four people were reported missing, over 9 400 houses collapsed or were damaged, and over 2.95 million hectares of farmland were damaged, with direct economic loss exceeding 4.4 billion RMB. In addition, at least 13 people were killed and 81 others were injured in Vietnam during the passage of Haiyan. Although Hong Kong was not directly in its path, one person was reported missing at Cheung Sha in Lantau Island and later confirmed dead after swimming in turbulent waves and swells whipped up by the high winds under the combined influence of Haiyan and the northeast monsoon.

A tropical depression formed over the southern part of the South China Sea about 280 km east of Nansha on 5 November and moved west to west-northwestwards. The estimated maximum sustained winds near its centre was about 55 km/h. The tropical depression made landfall over the coast of southern Vietnam the following day and dissipated inland.

Podul (1331) formed as a tropical depression over the southern part of the South China Sea about 130 km north-northeast of Nansha on 14 November and moved west to west- northwestwards. The estimated maximum sustained winds near its centre was about 55 km/h. Podul dissipated inland after making landfall over the coast of southern Vietnam the following day. Podul brought heavy rain and severe flooding to the central part of Vietnam, where at least 34 people were killed and 11 others were reported missing.

No tropical cyclone formed over the western North Pacific and the South China Sea in December.

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