1999 Pacific typhoon season.html



1999 Pacific typhoon season

Season summary map
First storm formed:	January 3, 1999
Last storm dissipated:	December 16, 1999
Strongest storm:	Bart - 898 hPa (mbar), 260 km/h (160 mph)
Total storms:	24
Typhoons:	11
Super typhoons:	1
Total fatalities:	At least 580
Total damage:	> $4.5 billion (1999 USD) > $5.8 billion (2008 USD)
Pacific typhoon seasons 1997, 1998, 1999, 2000, 2001

The 1999 Pacific typhoon season has no official bounds; it ran year-round in 1999, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean.

The scope of this article is limited to the Pacific Ocean, north of the equator and west of the international date line. Storms that form east of the date line and north of the equator are called hurricanes; see 1999 Pacific hurricane season. Tropical Storms formed in the entire west Pacific basin were assigned a name by the Joint Typhoon Warning Center. Tropical depressions in this basin have the "W" suffix added to their number. Tropical depressions that enter or form in the Philippine area of responsibility are assigned a name by the Philippine Atmospheric, Geophysical and Astronomical Services Administration or PAGASA. This can often result in the same storm having two names.

Storms

Tropical Storm Hilda (Auring)

Tropical storm (SSHS)
Duration	January 4—January 7
Intensity	65 km/h (40 mph) (1-min), 997 hPa (mbar)

The Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert for a developing broad circulation which stretched out from the northwest Borneo coast early on January 4. This developed into a tropical depression and moved slowly to the north away from the Borneo coast, becoming Tropical Storm Hilda early on January 6. Soon after reaching its peak strength of 65 km/h (40 mph) Hilda drifted further north into an area of increased wind shear, which caused the storm to dissipate the next day.¹ Both Japan Meteorological Agency and PAGASA tracked this system, but considered it a tropical depression. PAGASA named the storm Auring.²

Malaysia reported to the Typhoon Committee that Tropical Storm Hilda brought heavy rain to Sabah. This rain caused flooding and landslides, and was responsible for six deaths.¹ The mudslides caused about $1.3 million in damage (1999 USD, 15 million 1999 MYR) to roads throughout the country.³

Tropical Storm Iris (Bebeng)

Tropical storm (SSHS)
Duration	February 14—February 19
Intensity	65 km/h (40 mph) (1-min), 997 hPa (mbar)

A monsoon depression began to develop between Pohnpei and Chuuk on February 10 as it moved west.⁴ The JTWC issued a TCFA as the depression passed near Palau on February 13. The storm slowly consolidated as it moved towards the Philippines, becoming Tropical Storm Iris on February 17, but did not intensify any further. As the storm turned northwards under the influence of a subtropical ridge to the east it entered a high shear environment and rapidly degenerated, dissipating on February 19 220 km (140 miles) to the east of Luzon.⁵

PAGASA considered this storm to have been a tropical depression and named it Bebeng.⁴ Tropical Storm Iris had no effects on land.

Tropical Storm Jacob (Karing)

Tropical storm (SSHS)
Duration	April 6—April 10
Intensity	65 km/h (40 mph) (1-min), 997 hPa (mbar)

A low pressure area 220 km (140 miles) to the west of Yap developed into a tropical depression on April 6. It gradually developed as it moved to the west, becoming a strong depression with 55 km/h (35 mph) winds. It then began to accelerate to the northwest, becoming a minimal tropical storm as it did so. However, this northwards motion brought it into a region of increased shear, which weakened it back into a tropical depression. The low level circulation became completely exposed and the weakening system made landfall on southern Luzon on April 10.⁶ PAGASA named the system Karing and considered it a tropical depression.⁷

The rainfall from Jacob ranged from 80 mm (3 inches) up to 400 mm (16 inches) in some places, but only minor damage was recorded on land.⁸

Typhoon Kate (Diding)

Category 1 typhoon (SSHS)
Duration	April 22—April 28
Intensity	140 km/h (85 mph) (1-min), 967 hPa (mbar)

On April 22, a tropical disturbance which had developed in the Philippine Sea moved over Mindanao and intensified into a tropical depression whilst it was still overland. The depression soon moved overwater again as it tracked north to the east of the Philippines, becoming Tropical Storm Kate the next day. The JTWC initially forecast that the storm would only intensify slightly, as they predicted it to move north-northeast into an unfavorable environment. However, Kate instead moved on a more northerly route and entered an area with minimal wind shear. On April 26 Kate became a typhoon, the first of the season, and reached its peak strength with 140 km/h (85 mph) soon after. Later that day, the typhoon's motion acclerated to the northeast and it passed 9 km (6 miles) to the north of Iwo Jima. Kate then began to lose its convection and became an extratropical on April 28 to the northeast of Iwo Jima.⁹

Both JMA and PAGASA considered Kate to have been a tropical storm at its peak, in both cases considering this the first tropical storm of the season. PAGASA named the depression Diding soon after it formed and upgraded it to a tropical storm before the JTWC.⁷ Kate brought torrential rain to the north-east of the country, with amounts as high as 260 mm (14 inches) falling in places.¹⁰ The peak winds recorded on Iwo Jima were 95 km/h (60 mph), with gusts of up to 126 km/h (78 mph). There were no available damage reports following Kate for the Philippines or Iwo Jima.⁹

Typhoon Leo

Category 3 typhoon (SSHS)
Duration	April 27—May 2
Intensity	205 km/h (125 mph) (1-min), 933 hPa (mbar)

In late April a circulation began to develop within a monsoon depression in the South China Sea, forming into a tropical depression on April 27 when it was 710 km (440 miles) to the west of Manila. It strengthened as it moved to the west and became Tropical Storm Leo the next day. The storm then performed a cyclonic loop off the Vietnamese coast and began to intensify, becoming a typhoon as it moved to the northeast. As it moved towards China under a high-level ridge Typhoon Leo rapidly intensified to its peak with 205 km/h (125 mph) winds. However, it did not sustain this for long as it then moved northeast into a high shear environment and it weakened as it moved to the north. Leo made landfall on May 2 as a tropical depression, after the convection had become separated from the circulation of the storm and soon dissipated overland.¹¹

As Typhoon Leo was developing, its outer rainbands brought up to 130 mm (5 inches) to regions of Vietnam.¹² High waves caused by the typhoon sank a ship to the south of Hong Kong and only 7 of the 21 people on board were rescued. Peak sustained winds of 90 km/h (55 mph) were recorded on Waglan Island as Typhoon Leo passed to the south of Hong Kong and the storm dropped over 100 mm (4 inches) of rain on the territory. There was only light damage in Hong Kong as a result of Typhoon Leo, but the rainfall was responsible for 14 injuries, mostly in traffic accidents.¹³

Typhoon Maggie (Etang)

Category 3 typhoon (SSHS)
Duration	June 1—June 8
Intensity	195 km/h (120 mph) (1-min), 938 hPa (mbar)

The sixth tropical depression of the season formed in the monsoon trough to the east of the Philippines on June 1. The system intensifed as it moved to the north, becoming Typhoon Maggie 36 hours after it had formed. The typhoon intensified further as it began to head to the northwest into the Luzon Strait and it reached its peak with 195 km/h (120 mph) winds on June 5. The typhoon turned further to the west as it began to interact with Taiwan and started to weaken slowly. Maggie made landfall as a 150 km/h (90 mph) typhoon in southeastern China, to the east of Hong Kong on June 6. The storm then moved along the Chinese coast weakening as it did so. Maggie passed just to the north of Hong Kong before it turned into the mouth of the Pearl River and dissipated inland on June 8.¹⁴ Both the JMA and PAGASA considered Maggie a typhoon, and PAGASA named this storm Etang.¹⁵

The rainfall from Typhoon Maggie caused landslides in the Philippines that killed three people.¹⁴ The storm killed at two with another 5 people reported missing on Taiwan. The electricity supply to over 100,000 homes was cut off and there was over $18 million of agricultural damage on the island. Maggie brought sustained winds of up to 80 km/h (50 mph) and 85 mm (3.3 inches) of rain to Hong Kong. Two oil barges docked in the territory sank, one fully laden with oil which polluted a nearby beach. There were 5 injuries resulting from Maggie in the territory and the total damages were approximately $100,000. The typhoon killed four people and damaged over 3000 homes in Guangdong. At least 120 vessels were also damaged and there was more than $150 million of direct economic damage in the province.¹⁶ Maggie also brought rain of up to 100 mm (4 inches) to northern Vietnam, causing some localised flooding.¹⁷

Tropical Depression 07W

Tropical depression (SSHS)
Duration	July 15—July 18
Intensity	55 km/h (35 mph) (1-min), 1000 hPa (mbar)

An area of disturbed weather to the northeast of Guam slowly developed as it moved to the west, becoming a tropical depression on July 15. Soon after it formed the depression reached its peak strength with 55 km/h (35 mph) winds which it maintained for two days as it moved towards Honshū. Increased wind shear began to exposed the low level circulation and the depression began to weaken as it turned to the northeast. The depression dissipated on July 18 to the southeast of Honshū, having posed no threat to land.¹⁸

Tropical Depression 08W

Tropical depression (SSHS)
Duration	June 21—June 22
Intensity	55 km/h (35 mph) (1-min), 1000 hPa (mbar)

A tropical disturbance moving north to the east of Okinawa gradually developed as it moved to the north towards the Japanese mainland. On July 21 it began to intensify, becoming Tropical Depression 08W to the northeast of Okinawa. The depression strengthened slightly in the East China Sea before it made landfall near Changhung, South Korea on July 22. The storm became extratropical as it moved over the Korean peninsula and it entered the Sea of Japan, where it dissipated. The effects of Tropical Depression 08W are unknown.¹⁹

Tropical Storm Neil (Helming)

Tropical storm (SSHS)
Duration	July 25—July 28
Intensity	75 km/h (45 mph) (1-min), 994 hPa (mbar)

On July 23, a disturbance began to form in the Philippine Sea within the monsoon trough. The convection gradually consolidated as the disturbance moved north and the ninth tropical despression of the season formed on July 25 south of Okinawa. The depression passed near to the Japanese island and soon strengthened into Tropical Storm Neil. The storm turned slightly westward towards the Korean peninsula and reached its peak strength with 75 km/h (45 mph) winds on July 26. Neil made landfall to the southwest of Suncheon the next day as a minimal tropical storm and soon reemerged over the Yellow Sea as a tropical depression. There it interacted with a mid-latitude trough, that redirected back towards South Korea and it made a second landfall 35 km (25 miles) southwest of Seoul on July 28. Neil then quickly dissipated overland.²⁰

Both the JMA and PAGASA considered Neil a tropical storm, with PAGASA naming it Helming. Unusually, PAGASA assessed the storm as having reached a peak on July 22, when the JTWC still considered it a developing disturbance. This difference was due to a difference in opinion between the two centers as to where the storm's center was.²¹ There were reports of damage from flooding and winds gusts from Tropical Storm Neil in Japan, with a ferry running aground near Kannoura. Neil caused a fishing boat off the Korean coast to capsize, killing its crew of eight. There were wind gusts of up to 95 km/h (60 mph) on Cheju Island and the peak rainfall reported from the storm was over 200 mm (8 inches).²⁰ As the storm dissipated over Korea, it caused flash floods that killed at least 7 and left 7,000 homeless.²²

Tropical Depression 10W

Tropical depression (SSHS)
Duration	July 25—July 27
Intensity	45 km/h (30 mph) (1-min), 1002 hPa (mbar)

A tropical disturbance began to develop in the South China Sea on July 23 within the same monsoon trough that Tropical Storm Neil would develop from to the east. The disturbance became a tropical depression late on July 25 as it turned to the north towards the Chinese coast. It did not strengthen any further and made landfall near Shanwei as a minimal tropical depression on July 27. The depression then moved inland and dissipated, with no known effects.²³ The JMA considered Tropical Depression 10W to be a tropical storm, with peak 10-minute winds of 75 km/h (45 km/h), making 10W the second storm in 1999 that the JMA considered a tropical storm but the JTWC considered a depression.²¹

As the depression passed near Hong Kong, it dropped 31 mm (1.2 inches) of rain on the territory and sustained winds of 72 km/h (45 mph) were recorded on Waglan Island. There was no significant damage over land in the territory, though 18 swimmers were injured in the strong seas associated with the storm.²⁴

Typhoon Olga (Ising)

Category 1 typhoon (SSHS)
Duration	July 29—August 3
Intensity	150 km/h (90 mph) (1-min), 963 hPa (mbar)

On July 26, a disturbance began to develop at the eastern end of a well defined monsoon trough well to the east of the Philippines. The convection within the disturbance increased as it moved to the north and Tropical Depression 11W formed on July 29. The system continued to intensify, becoming Typhoon Olga two days later as it approached Okinawa. On August 1 Olga made landfall on the Japanese island as a typhoon, weakening slightly as it passed over the island. As it moved to the north-northwest it intensified to its peak with 150 km/h (90 mph) winds as it approached Korea. The storm was beginning to weaken as it passed to the west of Cheju Island on August 3 and it made a second brief landfall on the T'aean Peninsula before moving north in the Yellow Sea. The storm made its final landfall in North Korea as a strong tropical storm later that day with 100 km/h (65 mph) winds and became extratropical soon after.²⁵ Both the JMA and PAGASA considered Olga a typhoon, with PAGASA naming the storm Ising before the JTWC issued its first warning on the developing system.²¹

Although Typhoon Olga never approached the Philippines closely, it was responsible for heavy rains over much of Luzon that killed 160 people and displaced 80,000.²⁶ Olga passed over Okinawa, with winds of 80 km/h (50 mph) recorded at Kadena Air Base although damages on the island are unknown.²⁵ Torrential rain of up to 600 mm (24 inches) fell on the Korean Peninsula, with the highest totals falling near the border between North and South Korea.²⁷ The resulting floods and landslides caused 64 fatalities in South Korea and wind gusts of 96 km/h (60 mph) were reported near Seoul.²⁵ The flooding in South Korea destroyed about 400,000 square kilometres (150,000 sq mi) of rice paddies and 8,500 homes, leaving 25,000 people homeless.²¹ The Red Cross reported a further 42 deaths and 40,000 were made homeless from flooding in North Korea and that the flooding worsened the ongoing food shortages in the country.²⁸ Typhoon Olga brought the heaviest rains recorded in Korea for 25 years and caused a total of $657 million of damage in South Korea.²⁶

Tropical Storm Paul

Tropical storm (SSHS)
Duration	August 3—August 8
Intensity	95 km/h (60 mph) (1-min), 987 hPa (mbar)

Early in August, a low-level circulation center within a monsoon gyre to the southwest of Guam. On August 2 the JTWC issued a TCFA for the devleoping disturbance as it moved to the northwest, and it became Tropical Depression 12W the next day. On August 4 the depression became Tropical Storm Paul and began to merge with the gyre from which it had formed. As it merged with the gyre Paul strengthened to its peak with 95 km/h (60 mph) winds, to the east of Okinawa. After the two systems had merged, Paul turned briefly to the northeast and weakened to back into a tropical depression. The depression moved to the west brushing the south coast of Kyūshū on August 6 before dissipating in the Yellow Sea.²⁹

Tropical Storm Paul was highly unusual in that it formed from a monsoon gyre and then merged with it. Mergers of such systems rarely occur, it is much more common for tropical cyclones which form in this manner to move independently of the non-tropical system. Paul was also considered a tropical storm by the JMA, who reported that the rainfall from the storm caused landslides and flooding in western Japan.²⁹

Tropical Storm Rachel

Tropical storm (SSHS)
Duration	August 6—August 9
Intensity	65 km/h (40 mph) (1-min), 997 hPa (mbar)

A tropical disturbance formed within a monsoon trough just of the Chinese coast on August 6. The disturbance strengthened and became Tropical Storm Rachel as it moved east towards Taiwan. Rachel weakened back into a depression before it made landfall on the island and it dissipated over the Chungyang mountains on August 7. The remnants moved northeast into the East China Sea and the system redeveloped into a tropical depression the next day as it approached Okinawa. Rachel briefly became a minimal tropical storm for a second time as it approached the Japanese island, before it turned to the northwest. The storm entered an increasingly unfavorable environment and rapidly weakened on August 9.³⁰ Damage from Tropical Storm Rachel is unknown.

Tropical Depression 14W

Tropical depression (SSHS)
Duration	August 8—August 10
Intensity	45 km/h (30 mph) (1-min), 1000 hPa (mbar)

Tropical Depression 14W formed 120 km (75 miles) to the north of Iwo Jima on August 8. The depression, which had an exposed circulation center, moved to the north under the influence of a subtropical ridge over northern Japan. On August 9 it turned to the northwest and accelerated before its landfall near Owase the next day, with 45 km/h (30 mph) winds. The depression weakened as it passed north over Honshū and dissipated shortly after moving over the Sea of Japan.³¹

Tropical Depression 15W

Tropical depression (SSHS)
Duration	August 16—August 18
Intensity	45 km/h (30 mph) (1-min), 1002 hPa (mbar)

A tropical disturbance developed in the East China Sea on August 15 and gradually drifted towards Kyūshū. It intensified as it did so, becoming Tropical Depression 15W the next day. The fourth warning from the JTWC repositioned the cyclone much closer to the Kyūshū coast, where it made landfall near Ushibuka on August 17. The depression then drifted over Kyūshū and entered the Sea of Japan later that day, where it weakened. The storm dissipated on August 18 but its remnants were recognisable for a further two days.³² The depression's effects are unknown.

Typhoon Sam (Luding)

Category 1 typhoon (SSHS)
Duration	August 18—August 23
Intensity	140 km/h (85 mph) (1-min), 967 hPa (mbar)

On August 17, an area of circulation within the monsoon trough located in the Philippine Sea became more organized and the JTWC issued a TCFA. The developing cyclone slowly moved to the northwest, becoming Tropical Depression 16W nine hours after the TCFA was first issued. As the cyclone continued to intensify becoming Tropical Storm Sam on August 19, the subtropical ridge to the north shifted its track in a westwards direction towards Luzon. The storm passed over the north of the island on August 20 and entered the South China Sea reaching typhoon strength the next day. Sam gradually intensified further as it approached the Chinese coast and it made landfall about 19 km (12 miles) to the northeast of Hong Kong at its peak with 140 km/h (85 mph) winds on August 22. Sam continued to move to the northwest over China dissipating about 24 hours later.³³ PAGASA named the developing storm Luding shortly before the JTWC began to issue advisories.³⁴

Typhoon Sam was responsible for 7 deaths in the Philippines³³ and flooding from its rainfall displaced over 4000 people and landslides closed many major roads near Baguio City.³⁴ Sam became the wettest tropical cyclone to affect Hong Kong since records began in 1884, dropping over 616 mm (24.2 inches) of rain; exceeding the previous record set in 1926. Peak sustained winds of 96 km/h (60 mph) were recorded on Waglan Island as the typhoon passed over the territory. The heavy rain led to many instances of flooding and over 150 landslides throughout Hong Kong, killing 1 person and forcing the evacuation of about 1,000. A total of 328 people were injured in various incidents relating to the storm and total damage in Hong Kong totalled approximately $17 million.³⁶ In addition to the direct casualties from the storm, an China Airlines Flight 642, using an MD-11 aircraft, crashed while attempting to land at Hong Kong International Airport, killing 3 on board and injuring 219. At the time of the crash wind gusts in excess of 65 km/h (40 mph) were recorded at the airport.³⁷ After moving into China, Sam killed at least 17³³ and injured 100 people in Guangdong. Direct economic losses in the province were about $18 million.³⁶

Typhoon Tanya

Category 1 typhoon (SSHS)
Duration	August 19—August 24
Intensity	130 km/h (80 mph) (1-min), 972 hPa (mbar)

On August 19, Tropical Depression 17-W formed at a usually high latitude of over 30° N from a westwards moving low pressure area. The compact system intensified as it moved west under the influence of the subtropical ridge to the north, with the JTWC upgrading it to Tropical Storm Tanya early the next day. Tanya continued to slowly intensify, reaching its peak as a 130 km/h (80 mph) typhoon on August 22. The next day Tanya began to recurve through a weakness in the ridge to its north and increasing wind shear weakened the storm. The storm weakened further as it began to transition into an extratropical storm and the JTWC issued the final warning on the cyclone on August 24.³⁸

The JMA also monitored Tanya and made it a severe tropical storm at its peak. Post-season analysis increased the initial intensity of the system, making it a tropical storm before the JTWC began to issue full advisories on Tanya. Typhoon Tanya had no effects on land.³⁸

Typhoon Dora

Tropical storm (SSHS)
Duration	August 20—August 23
Intensity	110 km/h (70 mph) (1-min), 996 hPa (mbar)

Main article: Hurricane Dora (1999)

Hurricane Dora, the strongest storm of the 1999 Pacific hurricane season, crossed the International Date Line and entered the western Pacific on August 20. The final advisory from the Central Pacific Hurricane Center, while Dora was still in the eastern Pacific was for a minimal hurricane. As the storm crossed the Date Line, the JTWC assumed responsibility for the storm and downgraded it to a tropical storm on its first advisory. Once in the West Pacific, Tropical Storm Dora turned towards the northwest and weakened further as wind shear increased. Dora weakened to a tropical depression on August 22 well to the north of Wake Island and drifted to the north before dissipating the next day.³⁹

Dora became the first storm since 1994's John to have existed in all three Pacific basins and no significant damage was caused by the system anywhere along its path.⁴⁰

Tropical Depression 18W

Tropical depression (SSHS)
Duration	August 21—August 24
Intensity	55 km/h (35 mph) (1-min), 1000 hPa (mbar)

On August 21, a small tropical cyclone developed at the southern end of a westward moving shearline about 1200 km (750 miles) to the east of Tokyo. The depression strengthened slightly to its peak with 55 km/h (35 mph) the next day, before increasing vertical shear took its toll on the system. The increasingly exposed low level circulation of the storm accelerated to the north, towards the frontal system from which it had formed. Tropical Depression 18W became extratropical on August 24 to the east of Japan, having never approached land closely.⁴¹

Typhoon Virgil

Category 1 typhoon (SSHS)
Duration	August 24—August 29
Intensity	130 km/h (80 mph) (1-min), 972 hPa (mbar)

A tropical disturbance developed at the end of a shear line to the north of Iwo Jima on August 23. Vertical shear began to weaken and the JTWC began to issue advisories on Tropical Depression 19W the next day. The storm turned to the southwest and rapidly intensified on August 25, strengthening from a tropical depression to its peak as a 130 km/h (80 mph) typhoon in 12 hours. Virgil maintained typhoon strength for over a day before it entered a highly sheared environment in which it began to weaken again. Under the influence of a passing frontal system, the motion of the dissipating cyclone turned clockwise to the northeast. The storm dissipated on August 29 over water having never approached land.⁴² The JMA monitored Typhoon Virgil and made it a minimal severe tropical storm at its peak.

Tropical Storm Wendy (Mameng)

Tropical storm (SSHS)
Duration	September 1—September 4
Intensity	75 km/h (45 mph) (1-min), 994 hPa (mbar)

Late in August, a broad area of convection developed over a low pressure area in the Philippine Sea to the east of Luzon. The JTWC issued a TCFA for the developing system on August 31 and it developed into Tropical Depression 20W on September 1 as it moved to the west. The depression did not intensify as it moved to the northwest brushing the northeast tip of Luzon on September 2. After entering the South China Sea the storm turned more to the west and reached its peak as a 75 km/h (45 mph) tropical storm. It maintained this intensity until it made landfall in China 220 km (140 miles) east-northeast of Hong Kong the next day. The storm moved inland and dissipated soon after.⁴³ Both the JMA and PAGASA monitored Tropical Storm Wendy, with PAGASA naming this storm Mameng. PAGASA considered Wendy to have stronger winds than the JTWC, despite the fact that PAGASA uses a 10 minute averaging period to measure sustained winds, which generally results in a lower speed.³⁴

Tropical Storm Wendy fuelled severe rain over much of southern China in the week after it made landfall, with amounts as high as 500 mm (20 inches) recorded in northern Jiangxi and southern Zhejiang.⁴⁴ At least 133 people were killed and over 2,600 people were injured, with Wenzhou being particularly badly hit. Over 500,000 people had to be evacuated, over 2.2 million people had been affected by the storm and a local government spokesman called it "the most serious storm in a century". The direct economic damage in the region exceeded $275 million.⁴⁵ Whilst mainland China was severely affected by Wendy, the storm only had a minimal impact in Hong Kong.⁴³

Typhoon York (Neneng)

Category 1 typhoon (SSHS)
Duration	September 11—September 17
Intensity	130 km/h (80 mph) (1-min), 972 hPa (mbar)

A tropical disturbance developed on September 10, in the western Philippine Sea but initially failed to develop as it interacted with Luzon. The disturbance passed over Luzon and entered the South China Sea, where it became more organized and developed into Tropical Depression 21W late on September 11. The system gradually strengthened as it moved northwest towards the Chinese coastline, reaching its peak as a 130 km/h (80 mph) typhoon as it turned towards Hong Kong on September 16. York made landfall to the west of Hong Kong soon after and dissipated into a low pressure area over China the next day.⁴⁶ Both the JMA and PAGASA monitored York as a tropical storm, with PAGASA naming the system Neneng.⁴⁷

As the developing depression was crossing the Philippines, it brought heavy showers of up to 400 mm (16 inches), which caused some flooding in the Cagayan Valley⁴⁸ 18 people were killed in landslides in northern Luzon. As Typhoon York approached Hong Kong, the Hong Kong Observatory raised the No. 10 warning for the first time since 1983 and maintained it for 11 hours, the longest this level had ever been maintained. The peak sustained winds of 150 km/h (95 mph) were recorded on Waglan Island and the peak gusts of 234 km/h (146 mph) were the highest on record there. A total of 300 mm (12 inches) of rain fell on the territory as York passed directly over it and the resulting floods had a severe effect on agriculture throughout Hong Kong. Two people died in the storm and over 500 were injured, 11 seriously. Some 18,000 homes lost power in the wake of the storm and 4,000 trees were uprooted. Damage from the storm exceeded $10 million (USD) and direct economic losses were several billion Hong Kong Dollars. Transport in the territory was severely disrupted, with 470 flights cancelled and 80,000 passengers affected.⁴⁹

Two ships ran aground and a cargo ship sank, but all the crew were successfully rescued. One person was injured in Macau and 120 incidents related to the storm were reported there. After passing over Hong Kong, York killed 15 and injured 700 in Guangdong, with economic losses there exceeding $24 million (USD).⁴⁹ 10,000 people were left stranded by flooding in China after the storm and more than 10,000 trees were uprooted in Shenzhen.⁵⁰

Tropical Storm Zia

Tropical storm (SSHS)
Duration	September 13—September 15
Intensity	85 km/h (50 mph) (1-min), 997 hPa (mbar)

The JTWC began to track a disturbance in a monsoon trough to the west of the Marianas Islands on September 11. The disturbance moved to the north without any significant development until September 13, when the outflow of the system markedly improved and it soon developed into a tropical depression to the east of Okinawa. The depression strengthened further becoming Tropical Storm Zia later that day as approached Kyūshū. Zia peaked with 85 km/h (50 mph) winds as it made landfall on the island on September 14. The storm turned to the northeast and tracked over Japan and dissipated over central Honshū the next day.⁵¹

Tropical Storm Zia brought heavy rain to western Japan, which exceeded 500 mm (7.9 inches) in places. The resulting flooding and landslides prompted evacuations of over 14,000 people and stranded over 1,300 tourists in a Japanese mountain resort. Nine people died in Japan as a result of Tropical Storm Zia.⁴⁷

Tropical Storm Ann

Tropical storm (SSHS)
Duration	September 15—September 20
Intensity	85 km/h (50 mph) (1-min), 991 hPa (mbar)

Tropical Depression 23W formed about 165 km (105 mi) to the east of Okinawa on September 15, from a disturbance moving to the northwest under the influence of a subtropical high. As the system developed it turned first to the northwest and then to the west, becoming Tropical Storm Ann a day after forming. As Ann approached the Chinese coast to the north of Shanghai on September 18, it reached its peak with 85 km/h (50 mph) winds and began to recurve to the northwest. The storm started to weaken as it entered a higher shear environment. Ann captured by a mid-level trough moving through the region and turned to the east, rapidly weakening as it crossed the Yellow Sea. The system dissipated just off the South Korean coast near Mokpo early on September 20.⁵²

Tropical Storm Ann brought moderate rain of up to 100 mm (4 inches) to Anhui, Jiangsu and Shandong on September 18.⁵³ Rains of up to 200 mm (8 inches) from Ann and Typhoon Bart saturated South Korea and southwestern Japan, causing flooding and damage to rice paddies.⁵⁴

Super Typhoon Bart (Oniang)

Category 5 super typhoon (SSHS)
Duration	September 17—September 24
Intensity	260 km/h (160 mph) (1-min), 898 hPa (mbar)

Tropical Depression 24W developed on September 17, to the east of Taiwan. The storm drifted to the northwest, becoming Tropical Storm Bart on September 19 and reaching typhoon strength the next day. Bart intensified further as it turned to the northeast under the influence of upper-level winds. Typhoon Bart reached its peak on September 22 with 260 km/h (160 mph) winds when it passed 75 km (45 mph) to the west of Okinawa, becoming the only Super Typhoon during 1999. Bart began to weaken slowly as it continued north towards Kyūshū, Japan, which it struck on September 3 with 185 km/h (115 mph) winds. After crossing Kyūshū and westernmost Honshū the storm accelerated to the northeast in the Sea of Japan, becoming extratropical shortly before it reached northern Hokkaidō.⁵⁵ As Typhoon Bart formed in PAGASA's area of responsibility, it was named Oniang by PAGASA before moving to the north.⁴⁷

Typhoon Bart claimed at least two lives on Okinawa and brought over 710 mm (28 inches) of rain to the island.⁵⁵ Kadena Air Base was badly damaged by the typhoon with over $5 million of damage on the base.⁵⁶ Heavy flooding and landslides led to total of a 30 deaths and over 1,000 injuries in Japan. Over 800,000 homes lost power and 80,000 damaged in the aftermath of the storm. The worst damage was in Kumamoto Prefecture on Kyūshū, where 16 people died and over 45,000 homes were damaged. Bart affected the whole of Japan, with some minor damages occurring in Hokkaidō shortly after the storm became extratropical.⁵⁷ A large crane in Hiroshima collapsed killing 3 and injuring 4 people in the Mitsubishi plant there and the Itsukushima Shrine was also damaged.⁵⁸ Typhoon Bart was the costliest storm of the season, with total damages of $3.5 billion and further $5 million of damage to the Japanese economy.⁵⁹

Tropical Storm Cam

Tropical storm (SSHS)
Duration	September 23—September 26
Intensity	75