TROPICAL CYCLONES IN 2016

2.1 Review of tropical cyclones in 2016

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

In 2016, a total of 28 tropical cyclones occurred over the western North Pacific (WNP) and the South China Sea (SCS) bounded by the Equator, 45°N, 100°E and 180°, less than the long-term (1961-2010) average figure of around 30. During the year, 13 of the tropical cyclones attained typhoon intensity or above, less than the long-term average (1961–2010) of about 15, with seven of them reaching super typhoon intensity (maximum 10-minute wind speed of 185 km/h or above near the centre).

Figure 2.1 shows the monthly frequencies of the occurrence of tropical cyclones in WNP and SCS in 2016.

During the year, nine tropical cyclones made landfall over China, with three of them crossing the south China coast within 300 km of Hong Kong. Two tropical cyclones crossed Taiwan, five made landfall over Japan, five traversed the Philippines and five made landfall over Vietnam. With an estimated maximum sustained wind speed of 250 km/h and a minimum sea-level pressure of 890 hPa near its centre (Table 4.1), Super Typhoon Meranti (1614) in September (Figure 2.3) was the most intense tropical cyclone over the western North Pacific and the South China Sea in 2016.

2.1.2 Tropical cyclones in Hong Kong's area of responsibility

Amongst the 28 tropical cyclones in 2016, 15 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), slightly less than the long-term annual average figure of around 16 (Table 2.1). Only four of them developed within Hong Kong's area of responsibility. Altogether, 352 tropical cyclone warnings to ships and vessels were issued by the Hong Kong Observatory in 2016 (Table 4.2).

2.1.3 Tropical cyclones over the South China Sea

13 tropical cyclones affected SCS bounded by 10°N, 25°N, 105°E and 120°E in 2016, slightly more than the long-term annual average of around 12. Only four of them formed within SCS.

2.1.4 Tropical cyclones affecting Hong Kong

In 2016, the typhoon season in Hong Kong started on 26 May when a tropical depression formed in the northern part of the South China Sea and edged closer to the coast of western Guangdong, necessitating the issuance of the Standby Signal No. 1. The typhoon season ended with the cancellation of all tropical cyclone warning signals on 21 October as Tropical Storm Haima (1622) moved inland and weakened that day.

Nine tropical cyclones affected Hong Kong during 2016 (Figure 2.2), the highest since 1993 and more than the long-term (1961-2010) average of about six in a year (Table 2.2). They were Tropical Depression in May, Severe Tropical Storm Mirinae (1603) and Typhoon Nida (1604) in July, Tropical Storm Dianmu (1608) in August, Super Typhoon Meranti (1614) and Severe Typhoon Megi (1617) in September, Tropical Storm Aere (1619) and Super Typhoon Sarika (1621) and Haima (1622) in October. The No. 8 Gale or Storm Signal was issued during the passage of Nida and Haima, the highest tropical cyclone warning signal issued in 2016. The Strong Wind Signal No. 3 was issued during the passage of the Tropical Depression in May, Dianmu and Sarika. Mirinae, Meranti, Megi and Aere only necessitated the issuance of Standby Signal No. 1 in Hong Kong.

Relatively more tropical cyclones affecting Hong Kong in 2016 was mainly due to warmer-than-normal sea surface temperature near the Philippines and over the northern part of the South China Sea, as well as favourable atmospheric patterns over the western North Pacific that provided favourable steering flow for tropical cyclones to move towards the South China Sea.

2.1.5 Tropical cyclone rainfall

Tropical cyclone rainfall (total rainfall recorded at the Hong Kong Observatory Headquarters 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 2016 was 1033.9 mm (Table 4.8.1). This accounted for approximately 34.2 % of the year's total rainfall of 3026.8 mm and was about 42 % above the 1961-2010 long-term average of 728.8 mm.

Super Typhoon Sarika (1621) brought 491.3 mm of rainfall to the Hong Kong Observatory Headquarters (Table 4.8.1) and was the wettest tropical cyclone in 2016.

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.

JANUARY TO APRIL

No tropical cyclone formed over the western North Pacific and the South China Sea from January to April.

MAY

A Tropical Depression formed over the northern part of the South China Sea on the night of 26 May, it moved north-northwestwards and edged closer to the coast of western Guangdong. It took on a more northerly track the next day and slightly intensified, reaching peak intensity with an estimated sustained wind of 55 km/h near its centre. It made landfall near Yangjiang in western Guangdong on the evening of 27 May and soon degenerated into an area of low pressure that night.

According to press reports, the tropical depression brought rainstorms to western Guangdong. A bridge was destroyed by flood, causing a bus to plunge into the river and injuring two persons. At the Macao Maritime Ferry Terminal, two passengers were injured during an incident of vessel collision.

JUNE

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

JULY TO AUGUST

Nepartak (1601) formed as a tropical depression over the western North Pacific about 560 km south of Guam on 3 July. It moved northwest to west-northwestwards and intensified gradually. Nepartak developed into a super typhoon in the small hours of 6 July and reached its peak intensity with an estimated sustained wind of 230 km/h near its centre in the afternoon. After crossing the southern part of Taiwan on 8 July, Nepartak weakened into a typhoon. It continued to weaken as it entered the Taiwan Strait. Nepartak made landfall over the coast of Fujian on the afternoon of 9 July, and finally dissipated over inland Fujian on the morning of 10 July.

According to press reports, at least five people were killed and more than 400 injured in Taiwan during the passage of Nepartak. Nepartak and its remnant also brought severe damage to Fujian, Jiangxi and Guangdong. At least 69 people were killed and around 800 000 people affected, with direct economic loss exceeding 8 billion RMB.

Lupit (1602) formed as a tropical depression over the western North Pacific about 1 430 km east-northeast of Iwo Jima on the night of 23 July and tracked generally north-northeastwards. It intensified into a tropical storm the next day, reaching its peak intensity with an estimated sustained wind of 75 km/h near its centre. Lupit then turned north to north-northwestwards and finally transformed into an extratropical cyclone over the sea areas east of Japan in the small hours of 25 July.

Mirinae (1603) formed as a tropical depression over the central part of the South China Sea about 300 km east of Xisha on the night of 25 July. Moving west-northwestwards, it intensified into a tropical storm the next morning. Mirinae made landfall over the east coast of Hainan Island on the night of 26 July and weakened slightly while crossing Hainan Island.After entering Beibu Wan, Mirinae re-organized and re-intensified the next morning, becoming a severe tropical storm on the evening of 27 July and reaching peak intensity with an estimated sustained wind of 90 km/h near its centre. Mirinae made landfall over the coast of northern Vietnam that night and weakened gradually. It finally dissipated over northern Vietnam on the evening of 28 July. According to press reports, at least one person was killed, five were injured and many houses collapsed during the passage of Mirinae in Vietnam.

Nida (1604) formed as a tropical depression over the western North Pacific about 750 km east-southeast of Manila on the night of 29 July and moved north-northwestwards at first. Nida then took on a northwesterly track towards the Luzon Strait on the afternoon of 30 July and intensified gradually. After developing into a severe tropical storm on the morning of 31 July, it swept across the north coast of Luzon in the afternoon and entered the northeastern part of the South China Sea that night. Taking on a west-northwesterly track towards the coast of Guangdong, it further intensified into a typhoon and reached its peak intensity on the afternoon of 1 August with an estimated sustained wind of 130 km/h near its centre. Nida made landfall near Dapeng Peninsula around 3 a.m. on 2 August and moved across Shenzhen, passing just to the north of Hong Kong. It continued to weaken as it moved further inland, before finally degenerating into an area of low pressure over Guangxi early in the morning on 3 August.

According to press reports, about 500 000 people were affected and more than 300 houses collapsed in Guangdong, Guangxi, Hunan, Guizhou and Yunnan during the passage of Nida, with direct economic loss exceeding 500 million RMB. Business and schools were suspended in seven cities of Guangdong. Transportation services were paralyzed. Electricity supply to more than 16 000 households was affected in Shenzhen.

Omais (1605) formed as a tropical depression over the western North Pacific about 1010 km southeast of Iwo Jima on the afternoon of 4 August. Tracking generally northwards, Omais intensified gradually and developed into a severe tropical storm on 6 August, reaching its peak intensity with an estimated sustained wind of 105 km/h near its centre. It continued to take a north-northwesterly track towards the sea areas east of Japan over the next two days and weakened gradually, before finally evolving into an extratropical cyclone early in the morning on 10 August.

Conson (1606) formed as a tropical depression over the western North Pacific about 580 km west-southwest of Wake Island on the afternoon of 8 August. Tracking west to west- northwestwards, Conson intensified gradually and developed into a tropical storm in the small hours on 9 August, reaching its peak intensity that night with an estimated sustained wind of 85 km/h near its centre. It started to move north-northeastwards on 11 August and turned north-northwestwards two days later, before finally evolving into an extratropical cyclone over the sea areas east of Japan on the night of 14 August.

Chanthu (1607) formed as a tropical depression over the western North Pacific about 620 km south of Iwo Jima on the night of 13 August. Moving north-northeastwards, it intensified into a tropical storm that morning. Chanthu reached its peak intensity with an estimated sustained wind of 85 km/h near its centre early in the morning on 15 August and turned north-northwestwards. It skirted past the east coast of northern Honshu, Japan on the morning of 17 August, before evolving into an extratropical cyclone over the sea areas south of Hokkaido that afternoon. According to press reports, Chanthu brought torrential rain to the Tohoku region of Japan during its passage. Power supply to about 1 800 households was suspended, and transportation services were affected.

Tropical Depression Dianmu (1608) formed over the northern part of the South China Sea about 220 km southwest of Hong Kong on 17 August. It moved slowly that day and intensified gradually. Dianmu intensified into a tropical storm the next morning. Moving generally westwards, Dianmu made landfall over Leizhou Peninsula on the afternoon of 18 August and entered Beibu Wan that night. It re-intensified as it moved across Beibu Wan, reaching its peak intensity with an estimated sustained wind of 85 km/h on the morning of 19 August. After making landfall over the northern part of Vietnam in the afternoon, Dianmu moved inland and weakened gradually. It finally degenerated into an area of low pressure over the northern part of Myanmar on the morning of 20 August. According to press reports, there was flooding in many places in Hainan Island due to rainstorms brought by Dianmu. Around 40 000 people were evacuated and transportation services were affected. In Vietnam, a least 16 persons were killed, two were reported missing and another 15 were injured during the passage of Dianmu.

Meanwhile, three tropical depressions formed in quick succession over the western North Pacific on 19 – 20 August: Mindulle (1609) about 810 km south of Iwo Jima on the morning of 19 August, followed by Lionrock (1610) about 350 km south-southeast of Tokyo and Kompasu (1611) about 960 km east-southeast of Tokyo that night.

Kompasu tracked northwestwards and intensified into a tropical storm on the morning of 20 August, reaching its peak intensity with an estimated sustained wind of 65 km/h near its centre. Kompasu turned northwards on 21 August off the east coast of northern Honshu, Japan and evolved into an extratropical cyclone that night over the east coast of Hokkaido. According to press reports, at least one person was killed and three were injured in Hokkaido during the passage of Kompasu. Over 130 houses were flooded.

Tracking generally northwards after formation, Mindulle intensified into a tropical storm on the morning of 20 August and developed further into a severe tropical storm the next day, reaching its peak intensity on the morning of 22 August with an estimated sustained wind of 110 km/h near its centre. Mindulle made landfall east of Tokyo that day and swept across northern Honshu along a north-northeastward track. It finally evolved into an extratropical cyclone over the sea areas north of Hokkaido on 23 August.

Mindulle was the third tropical cyclone to strike eastern Japan in less than a week. According to press reports, Mindulle brought squalls and heavy rain to Honshu and Hokkaido during its passage. At least two persons were killed and over 60 were injured. Transportation services were affected.

But the sixth and most destructive cyclone to hit eastern Japan in a stormy August was yet to come. Though forming closest to Japan among its contemporaries, Lionrock initially tracked generally southwestwards away from Honshu due to its interaction with Kompasu and Mindulle. It started to slow down on the morning of 21 August and after drifting southeastwards for a while, it resumed a southwestward track on 23 August. Lingering for days over the sea areas east of the Ryukyu Islands, Lionrock continued to intensify and became a severe typhoon on the night of 24 August, reaching its peak intensity with an estimated sustained wind of 175 km/h near its centre early next day. Making a sharp U-turn, it started to track northeastwards on 26 August and headed back towards where it came from. After weakening into a typhoon on the afternoon of 29 August, Lionrock turned to the north-northwest heading straight towards northern Honshu. It swept across the Tohoku region the next day before evolving into an extratropical cyclone over the Sea of Japan on the morning of 31 August.

According to press reports, at least 12 people were killed, another five were reported missing and around 180 000 people had to be evacuated in the Tohoku region and Hokkaido during the passage of Lionrock. There were extensive flooding and landslides, and many houses were damaged. Transportation services were paralyzed.

SEPTEMBER TO OCTOBER

Namtheun (1612) formed as a tropical depression over the western North Pacific about 370 km south of Okinawa on the early morning of 1 September. It moved northeastwards and intensified rapidly that day. Namtheun turned northward the next day and developed into a severe typhoon, reaching its peak intensity with an estimated sustained wind of 165 km/h. Namtheun subsequently started to weaken and after skirting the west coast of Kyushu, Japan, degenerated into an area of low pressure over the Sea of Japan on 5 September. According to press reports, Namtheun brought torrential rain and high winds to Kyushu. At least one person was injured and over 1 700 people were evacuated.

Malou (1613) formed as a tropical depression over the western North Pacific about 100 km west-northwest of Okinawa on the afternoon of 6 September, it moved northeastwards with an estimated sustained wind of 55 km/h. Malou evolved into an extratropical cyclone over the seas south of Japan early in the morning on 8 September.

Meranti (1614) formed as a tropical depression over the western North Pacific about 390 km west of Guam on the early morning of 10 September. It moved west-northwestward and intensified rapidly. Meranti developed into a super typhoon on 12 September and reached its peak intensity the next day with an estimated sustained wind of 250 km/h. After crossing the Luzon Strait on the night of 13 September, Meranti tracked northwestward and moved over the coastal waters of southwestern Taiwan the next day, heading towards Fujian and weakening gradually. Meranti made landfall near Xiamen on the early morning of 15 September and moved inland, before degenerating into an area of low pressure over Jiangxi early in the morning on 16 September.

According to press reports, at least two persons were killed and 63 were injured in Taiwan during the passage of Meranti. Electricity and water supply for over one million households were disrupted. Transportation services were paralyzed. Meranti also wreaked havoc in Fujian and Jiangxi, resulting in at least 29 deaths, 15 missing, and about 2.5 million people affected with the collapse of around 18 000 houses. Direct economic losses exceeded 11.7 billion RMB.

Rai (1615) formed as a tropical depression over the central part of the South China Sea about 500 km east-southeast of Da Nang on the morning of 12 September. It took on a west- northwesterly track towards the coast of Vietnam with an estimated sustained wind of 55 km/h near its centre at peak intensity. Rai made landfall over the central part of Vietnam on the early morning of 13 September and dissipated over Thailand that afternoon. According to press reports, Rai brought torrential rain to Vietnam. At least two persons were killed and 33 people were injured. Many houses were damaged.

Malakas (1616) formed as a tropical depression over the western North Pacific about 340 km west of Guam on the afternoon of 12 September. Taking a west-northwesterly to northwesterly track across the sea areas east of Luzon, it intensified gradually. Malakas developed into a severe typhoon on the early morning of 16 September and turned north-northwestwards across the seas east of Taiwan during the day. Malakas reached its peak intensity the next day with an estimated sustained wind of 175 km/h near its centre. It turned northeastwards on 18 September and swept across Japan on the night of 19 September and the next day, before evolving into an extratropical cyclone over southern Honshu during the night.

According to press reports, transportation services were affected in Taiwan during the passage of Malakas. Malakas also brought torrential rain and high winds to extensive areas in southern Japan, resulting in at least two deaths, one missing, 42 injuries and evacuation of about 300 000 people. Electricity supply for over 140 000 households in Kyushu was disrupted.

Megi (1617) formed as a tropical depression over the western North Pacific about 300 km south-southwest of Guam on the morning of 22 September. Moving generally northwestwards at first, it turned to the west-northwest the next day and intensified gradually. Megi developed into a severe typhoon over the sea areas east of Taiwan on the small hours of 26 September, reaching its peak intensity the next day with an estimated sustained wind of 175 km/h near its centre. Megi made landfall near Hualien in Taiwan and weakened on the afternoon of 27 September. After entering the Taiwan Strait, it continued to track west-northwestward in the general direction of Fujian. It made landfall again near Quanzhou on the morning of 28 September and moved inland across Fujian, before finally degenerating into an area of low pressure over Jiangxi early in the morning on 29 September.

According to press reports, Megi wreaked havoc in Taiwan, resulting in at least four deaths and over 500 injuries. Business and schools were suspended in all cities and transportation services were paralyzed. Agricultural damage was estimated to exceed NT$ 1 billion. Megi also brought torrential rain and ferocious winds to Fujian, Zhejiang and Jiangxi. At least six people were killed, 33 missing and over 600 000 people were evacuated. Direct economic losses exceeded 2.58 billion RMB.

Chaba (1618) formed as a tropical depression over the western North Pacific about 570 km east-northeast of Guam on the early morning of 28 September. Moving generally westward at first, it turned north-northwestwards on 30 September in the general direction of the Ryukyu Islands and intensified gradually. Chaba developed into a super typhoon on the early morning of 3 October, reaching its peak intensity at night with an estimated sustained wind of 220 km/h. After sweeping past the Ryukyu Islands, it moved across the East China Sea on a northerly track towards the southern part of the Korean Peninsula and finally evolved into an extratropical cyclone over the sea areas north of Honshu, Japan on the night of 5 October.

According to press reports, transportation services in Okinawa were seriously affected during the passage of Chaba. Chaba also wreaked havoc and caused extensive flooding in the southern part of the Republic of Korea, resulting in at least seven deaths with three others missing. Electricity supply to about 25000 households in Jeju was interrupted.

Aere (1619) formed as a tropical depression over the western North Pacific about 900 km east of Dongsha on the afternoon of 5 October. Moving west to west-northwestwards, it moved across the Luzon Strait and entered the northeastern part of the South China Sea the next day while intensifying into a tropical storm. After crossing the sea areas south of Dongsha in the early morning on 7 October, Aere slowed down and drifted northwards during the day, reaching its peak intensity in the afternoon with an estimated sustained wind of 85 km/h near its centre. Aere moved northeastwards slowly on 8 October and became almost stationary the next day as it weakened gradually. Aere picked up speed and turned to move southwestwards on 10 October, degenerating into an area of low pressure near Dongsha that night. However, its remnant low pressure area continued to track to the southwest towards the sea areas around Xisha over the next couple of days. It re- intensified into a tropical depression south of Hainan Island on the morning of 13 October and turned westwards. After making landfall over the central part of Vietnam early next morning, Aere weakened into an area of low pressure before dissipating further inland.

According to press reports, the outer circulation of Aere brought heavy rain to southern Taiwan and caused flooding in some areas. Land and sea transportation services were affected.

Songda (1620) formed as a tropical depression over the western North Pacific about 1600 km east-southeast of Iwo Jima on the afternoon of 8 October. It moved generally northwestwards and intensified gradually. Songda developed into a typhoon over the sea areas east of Iwo Jima on the morning of 10 October and turned northwards. It picked up speed towards the northeast and intensified into a super typhoon over the next couple of days, reaching its peak intensity with an estimated sustained wind of 185 km/h near its centre before finally evolving into an extratropical cyclone on 13 October.

Sarika (1621) formed as a tropical depression over the western North Pacific about 1060 km east of Manila on the morning of 13 October. Taking a west-northwesterly track towards the Philippines, it intensified into a tropical storm that night. Sarika further intensified rapidly the next day and developed into a super typhoon on the night of 15 October, reaching its peak intensity with an estimated sustained wind of 185 km/h near its centre. Sarika weakened into a typhoon while moving across Luzon in the early morning on 16 October. It re-organized after entering the South China Sea. Sarika made landfall over Hainan Island on the morning of 18 October and turned northwestwards. It moved across Beibu Wan on 19 October and dissipated over inland Guangxi later that day.

According to press reports, at least three persons were killed and three others were missing in the Philippines during the passage of Sarika. There were extensive landslides and many houses collapsed. In Guangdong, Guangxi and Hainan, at least 3.7 million people were affected with direct economic loss of around 5.5 billion RMB.

Haima (1622) formed as a tropical depression over the western North Pacific about 710 km south of Guam on the afternoon of 14 October. Moving generally northwestwards, Haima intensified gradually and developed into a super typhoon on the night of 17 October. Tracking to the west-northwest, it reached its peak intensity the next day with an estimated sustained wind of 230 km/h near its centre. Haima moved across northern Luzon on the early morning of 20 October and weakened into a typhoon. It then moved northwestwards and entered the northeastern part of the South China Sea during the day. Haima turned northwards on 21 October and made landfall near Shanwei in eastern Guangdong that afternoon, before finally degenerating into an area of low pressure over Jiangxi during the night.

According to press reports, Haima wreaked havoc in northern Luzon with extensive flooding and landslides as well as the collapse of many houses. At least eight people were killed and more than 90000 people had to be evacuated. Haima also brought heavy rain and squalls to Guangdong and Fujian. At least 1.8 million people were affected and around 600 houses collapsed. Transportation services were seriously affected and the direct economic loss exceeded 5 billion RMB.

NOVEMBER

Meari (1623) formed as a tropical depression over the western North Pacific about 230 km north-northeast of Yap early in the morning on 2 November, and moved north-northwestwards and northwards slowly. Meari started to accelerate northeastwards and intensified gradually on 4 November. It developed into a typhoon the next day, reaching its peak intensity with an estimated wind of 140 km/h near its centre. Meari finally evolved into an extratropical cyclone over the western North Pacific southeast of Japan on the night of 7 November.

Ma-on (1624) formed as a tropical depression over the western North Pacific about 1610 km east of Guam on the afternoon of 9 November and moved generally west-northwestwards. Ma-on intensified into a tropical storm on the afternoon of 10 November, reaching its peak intensity with an estimated wind of 65 km/h near its centre. It then started to weaken gradually and degenerated into an area of low pressure over the sea areas southeast of Iwo Jima on 12 November.

Tokage (1625) formed as a tropical depression about 830 km southeast of Manila on the afternoon of 24 November and moved across the Philippines on a west-northwestward to northwestward track. It entered the South China Sea on 26 November and intensified into a severe tropical storm, reaching its peak intensity with an estimated wind of 90 km/h near its centre. Tokage turned slowly to the northeast on 27 November and lingered over the sea areas west of Luzon. Affected by the northeast monsoon, Tokage weakened rapidly and dissipated the next day.

DECEMBER

A tropical depression formed off the coast of southern Vietnam about 370 km east- southeast of Ho Chi Minh City on the afternoon of 12 December. It moved northwest slowly with an estimated sustained wind of 45 km/h near its centre. The tropical depression made landfall over southern Vietnam the next morning and dissipated inland during the day.

Nock-ten (1626) formed as a tropical depression over the western North Pacific about 490 km southeast of Yap on the afternoon of 21 December. It moved northwestwards and intensified rapidly. Nock-ten developed into a super typhoon on 24 December, reaching its peak intensity with an estimated wind of 210 km/h near its centre. It took a westerly track across the central part of the Philippines and entered the South China Sea on the afternoon of 26 December. Affected by an intense northeast monsoon, Nock-ten turned southwestwards and dissipated over the central part of the South China Sea the next day. According to press reports, at least six people were killed and eight were missing in the Philippines during the passage of Nock-ten. Over 380 000 people were forced to leave their homes.

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