The 1997 Pacific typhoon season has no official bounds; it ran year-round in 1997, 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. This was the most active tropical cyclone season ever recorded, with a record ten Category 5 storms forming and with an ACE of 594.11.
The season was unusual in the number of super typhoons that occurred in the basin, with eleven typhoons reaching winds of at least 135 knots. They were Isa, Nestor, Rosie, Winnie, Bing, Oliwa (from Central Pacific), Ginger, Ivan, Joan, Keith, and Paka (from Central Pacific). This was due to the strong El Niño of 1997-1998, which contributed to the record amounts of not only super typhoons but also tropical storms in the Western and Eastern Pacific. Fortunately, most of the stronger systems remained at sea.
When Severe Tropical Storm Peter made landfall in southern Japan on June 27, it marked the first time that two tropical cyclones made landfall in mainland Japan during the month of June since reliable records began in 1951. According to the Joint Typhoon Warning Center, eleven tropical cyclones attained super typhoon status, ten of which became Category 5 Super Typhoons, marking the highest number of Category 5 storms in a single season on record.
In early January, an area of convection developed along a near-equatorialtrough just west of the International Date Line. It tracked steadily westward, and remained disorganized for about week. On January 18, deep convection increased as a low-level circulation began to form, and at 0000 UTC on January 19 it developed into Tropical Depression 01W while located to the southwest of Guam. Based on satellite imagery estimates, the Joint Typhoon Warning Center upgraded it to Tropical Storm Hannah six hours after first forming. The deep convection quickly organized into well-defined cyclonic bands, and early on January 20 Hannah attained its peak intensity of 60 mph near the island of Yap. Increased southeasterly wind shear weakened the storm, leaving its dwindling convection situated along the northern portion of the circulation. Interaction with a large and powerful extratropical cyclone left the storm moving erratically, and on January 22 Hannah weakened to tropical depression status. Its motion turned to a steady southwestward motion, and on January 27 Hannah dissipated a short distance east of the Philippine island of Mindanao.
Isa developed from a disturbance in the monsoon trough near the Caroline Islands on April 12. It moved erratically at first, though after attaining tropical storm status it curved westward due to the subtropical ridge to its north. Isa very gradually intensified, and on April 20 the typhoon reached peak 1-min winds of 270 km/h (165 mph), as reported by the Joint Typhoon Warning Center; Japan Meteorological Agency reported maximum 10-min winds of 155 km/h (100 mph). After turning northward, it accelerated to the northeast, and merged with a larger extratropical cyclone on April 24.
Early in its duration, Isa caused light rainfall and moderate winds on Pohnpei. Later, a stationary rainband from the typhoon dropped heavy precipitation on Guam during its dry season. Damage in the Guam National Weather Service area of responsibility totaled $1 million (1997 USD, $1.3 million 2006 USD), the majority of it from crop damage. No deaths were reported.
A low-level equatorial westerly wind system developed an area of convection on April 18, the same system that previously developed Typhoon Isa. It drifted west-northwestward, and on April 21 separated from the westerly wind system. At 0400 UTC on April 22, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert on the system, and two hours later the JTWC issued the first warning on Tropical Storm Jimmy about 1360 km (845 mi) southeast of Guam. Coinciding with its first warning, the Japan Meteorological Agency (JMA) classified it as a tropical depression.
Jimmy continued northwestward through a break in the subtropical ridge caused by Isa, and it steadily intensified as it tracked through an area of light vertical wind shear. It recurved to the northeast, and shortly after reaching its westernmost point Jimmy attained its peak intensity of 55 mph on April 24. Conversely, JMA assessed Jimmy as remaining a minimal tropical storm throughout its duration. After maintaining peak winds for about 18 hours, to increased southwesterly winds aloft quickly weakened the storm, and late on April 25 JTWC issued its final advisory on Jimmy after its low-level circulation center became completely exposed from the deep convection. On April 26, Jimmy was absorbed by an approaching frontal trough over the open Pacific Ocean. The storm had little effects on land.
A low-level equatorial trough developed an area of convection on May 4. The low strengthened as it became more organized over the next two days. Late on May 6, the JTWC issued a TCFA and the system was declared Tropical Depression 04W shortly after. The depression slowly intensified and was upgraded to a Tropical Storm early on May 8 and was named Kelly. Kelly was able to intensify slightly before strong vertical wind shear displaced the center, weakening Kelly. Kelly was downgraded to a Tropical Depression on May 10 and the remnant circulation dissipated the next day.
Tropical Depression 5W drifted eastward through the Philippines in late May. The depression continued northeastward, becoming a tropical storm, and transitioning to an extratropical storm on May 30. In the Philippines, Levi killed 53 people and displaced 210,000 others.
On June 23, a large area of convection grouped together to form a low pressure, over the Mariana Islands. It strengthened into a tropical depression on June 26, before intensifying into a category 1 typhoon 2 days later. Marie then reached its peak intensity on June 31, as a category 2 typhoon, before undergoing a Eyewall replacement cycle. The storm developed double eyewalls during the process. On June 2, the system degenerated into a extratropical cyclone.
In Late May, an area of convection developed near the Marshall Islands, and rapidly became a low pressure area. On June 1, the low pressure area organized into a tropical depression. Nestor intensified into a category 1 typhoon on June 7, as it started to affect the Mariana Islands. Nestor continued to intensify, and on June 10, Nestor reached its peak intensity as a category 5 super typhoon, as the storm began to affect the Northern Mariana Islands. At this time, Nestor began showing annular characteristics. Nestor began to weaken slowly, as typical annular typhoons do, while it developed an eye measuring 65 kilometers across. On June 15, Nestor transitioned into a extratropical cyclone, as it weakened.
In preparation for Opal, Japanese airlines cancelled 107 domestic flights and port officials halted all ferry traffic. Throughout Japan, 6,750 schools were closed due to the typhoon. One person drowned after being knocked off his boat by rough seas while trying to secure it at port. Heavy rains flooded streets throughout the region. The storm triggered 14 landslides, flooded 50 homes and cut power to 800 residences. In all, three people were killed in Japan by Typhoon Opal.
From June 22–26, PAGASA tracked the storm, and named it Daling.
Ahead of the storm, international and domestic flights were cancelled throughout Japan and ferry service was suspended. Heavy rains produced by the storm triggered landslides throughout Japan, resulting in three fatalities. A landslide caused a train derailment that left 28 people injured after covering the tracks. One of the fatalities from the storm was that of a United States soldier stationed in Iwakuni. The JMA estimated that upwards of 14 in (360 mm) of rain fell due to Typhoon Peter.
On July 18, Tropical Depression 10W formed near Caroline Islands. 10W was upgraded to Tropical Storm Rosie and became a Category 5 Super Typhoon on July 22. Rosie moved northward and began to weaken. Rosie made a landfall as a Category 1 typhoon at Shikoku, Japan on July 26. In Japan, five people were killed and 1,200 were displaced by the storm.
In the middle of July, a mid-level circulation formed within the Tropical Upper Tropospheric Trough. The circulation built toward the surface, and by July 20 the system developed a low-level circulation with scattered associated convection. Based on its organization, the Japan Meteorological Agency (JMA) classified the system as a weak tropical depression early on July 20 while located about 820 km (510 mi) northeast of Farallon de Pajaros, the northernmost island in the Northern Mariana Islands. Early development was impeded by the outflow from Typhoon Rosie; after drifting northwestward for 2 days the system turned to the northeast, and by July 24 the influence from Rosie greatly diminished. Accordingly, the organization of the depression quickly increased, and on July 24 the Joint Typhoon Warning Center (JTWC) classified it as Tropical Depression 11W.
A building anticyclone to its northwest forced the depression southeastward. It became steadily less organized, and on July 26 JTWC issued a final warning on the system, believing it to be dissipating. Shortly thereafter, however, the system began re-organizing, and on July 27 the system developed into Tropical Storm Scott. The storm tracked northwestward, then westward, and finally turned to the northeast. Scott gradually strengthened to attain peak winds of 105 km/h (65 mph) on July 29. JMA had upgraded the depression to tropical storm status on July 28, and assessed its peak intensity at 75 km/h (45 mph). Scott maintained its peak intensity for about 12 hours before slowly weakening as it accelerated northeastward. On August 2, the storm merged with an approaching frontal trough, and the following day JMA considered Scott dissipated while located near the Alaskan island of Gareloi. Tropical Storm Scott never affected land. The storm was the only tropical cyclone during the season to not form from the monsoon trough.
On August 5, a tropical depression formed near the Marshall Islands. It headed northwestward, slowly strengthening to a tropical storm on the 9th. Intensification became more rapid as conditions became more favorable, and Winnie reached typhoon strength on the 10th. 2 days later, it became the 4th Super Typhoon of the season with peak winds of 160 mph. Soon after, the eye became ragged and large, with an outer eyewall reaching 200 miles in diameter. On the 18th, a minimal Typhoon Winnie passed north of Taiwan and hit eastern China, where it winded down until dissipating on the 19th. The remnant continued northeastward, bringing heavy rain and damage across China until the 23rd. In all, Winnie killed 212 people, displaced over 1 million, and caused $4.1 billion in damages.
Tropical Depression 16W developed out of a weak tropical disturbance on August 13. The disturbance was relatively close to another disturbance which would eventually become Typhoon Yule. By August 17, the disturbance had developed sufficient convection to be declared a tropical depression. However, upon being classified a depression, it was already beginning to be influenced by the nearby Yule. 16W eventually was overcome by Yule and a merger of the two systems took place on August 19, leading to the dissipation of the depression.
Originating from a tropical disturbance over the South China Sea on August 19, Zita tracked westward as it quickly strengthened within a region of light wind shear, attaining winds of 140 km/h (85 mph) as it made landfall along the Leizhou Peninsula early on August 22. Maintaining this intensity, the storm made a second landfall in northern Vietnam later that day before rapidly weakening over land. The remnants of Zita were last noted over extreme northwestern Vietnam on August 24. Early in its existence, the storm was monitored by PAGASA and was designated with the local name Luming. Throughout Zita's path, seven people were killed and $438 million was wrought in damage, nearly all of which took place in China.
Typhoon Amber was the eighteenth tropical cyclone of the season. The tropical depression initially tracked slowly west-northwest between the subtropical ridge and Typhoon Zita and developed at a faster than normal pace. By August 26, Tropical Storm Cass formed to the west-southwest, which accelerated Amber's forward motion to the northwest due to a fujiwara interaction. It underwent eyewall replacement cycles from August 25 through August 27, and tracked across Taiwan/Taipei with maximum sustained winds of 95 knots, then through the Formosa Strait into China as a minimal typhoon. On August 30, Amber completely absorbed Cass, in inland China, before degenerating into a remnant low, and dissipating as well, later on that day. Damages from Typhoon Amber amounted to $52 million.
As a tropical storm, Bing tracked through the Mariana Islands and produced torrential rains. Following previous heavy rains earlier in the month, a maximum of 6.17 in (157 mm) at Andersen Air Force Base on Guam and 5.19 in (132 mm) on Tiyan. A landslide in Santa Rita caused significant structural damage. By September 1, Bing bypassed the Bonin Islands. Sustained winds reached 55 km/h (34 mph) and gusts peaked at 75 km/h (47 mph). The extratropical remnants of Bing brought heavy rain to the Aleutian Islands between September 6 and 7. Winds also gusted in excess of 95 km/h (60 mph) in some areas.
On August 25, a low pressure area developed in the South China sea, west of the Philippines, associated with the dissipating convection of Tropical Storm Zita (1997). The low pressure area then started to strengthen, and slowly became a Tropical Depression on August 28. The system failed to strengthen for a while, due to a much stronger system just east of Cass, Typhoon Amber. However, Typhoon Amber soon started to move north, just a little farther from Cass, but was just enough for Cass to strengthen into a Tropical Storm. As the nearby Typhoon Amber started to make landfall over Taiwan, a strong southern inflow from Typhoon Amber pulled Cass northwards, in an effect known as the Fujiwhara effect. As Typhoon Amber made landfall, and moved inland over Eastern China, Cass was pulled very close to Typhoon Amber, while Cass was maintaining Tropical Storm strength. This severely weakened the storm, as it made landfall on August 30. Cass was then absorbed by Typhoon Amber, shortly afterwards, in inland China.
On September 2, the monsoon formed into Tropical Depression 2C in the Central Pacific. It headed slowly westward, becoming a tropical storm on September 3. Later that day, Oliwa crossed the International Date Line, and continued to slowly strengthen to become a typhoon on September 8. Oliwa rapidly strengthened on September 9 to reach a peak of 160 mph winds; the sixth Super Typhoon of the year. Oliwa slowly weakened as it moved westward, and hit Japan on September 15 and September 16. It turned to the northeast, and dissipated on September 17. In Japan, severe flooding from the typhoon killed 17 people and displaced 30,000 others.
During mid-September, a monsoonaltrough developed in the South China Sea. Deep convection developed near the periphery of the low level circulation before rapidly consolidating near the center on September 20. At this time, the JTWC classified the system as Tropical Depression 22W while situated near the coast of Vietnam. Due to the proximity to land, the system struggled to develop until it turned sharply to the east on September 22.
In Vietnam, Fritz killed 28 people and caused $5.1 million in damages.
Typhoon Ginger originated from a low-latitude tropical disturbance near the International Date Line on September 21. The following day, deep convection consolidated around a low-level circulation center and banding features formed around the system. At 0530 UTC, the JTWC issued a tropical cyclone formation alert for the system. Later that day, the system was designated as Tropical Depression 24W. Tracking in a more northerly direction, the depression intensified into a tropical storm the next day, at which time it was given the name Ginger. Continued strengthening occurred at a climatological rate until it was upgraded to a typhoon on September 25. Upon becoming a typhoon, Ginger underwent a period of explosive development.
During this period, the storm intensified into a Category 5 super typhoon, with winds reaching 265 km/h (165 mph) by 0000 UTC on September 27. At this time, Ginger featured a small, well-defined eye surrounded by a smooth central dense overcast and large convective feeder bands. The general cloudless environment surrounding the system allowed outflow to cover a large area. Shortly after peaking, the storm began to recurve towards the northeast and weaken. Gradually accelerating, the storm began to undergo an extratropical transition. The JTWC issued their final advisory on the typhoon at 0600 UTC on September 30. Several hours later, the extratropical system weakened below typhoon intensity. The remnants of Ginger persisted for two more days as it rapidly tracked towards the Western United States. By October 2, the storm impacted the region and dissipated shortly thereafter.
The remnants of Typhoon Ginger brought strong winds and heavy rain to the Western United States. Winds along the Oregon coastline gusted up to 69 mph (111 km/h). The highest rainfall total was recorded in Felida, Washington at 1.3 in (33 mm). Power was also briefly cut to 450 people by the high winds.
Tropical Depression 26W developed out of an area of disturbed weather located near the Mariana Islands on September 29. While passing near Guam, the disturbance was designated a tropical depression. Shortly after, the depression became disorganized as wind shear displaced the convection associated with the storm. Over the next 24 hours, the depression stalled in response to weak steering currents before a subtropical ridge developed to the north and caused the system to move quickly to the west. The low became separated from almost all of its convection on October 6 before being absorbed into a frontal system the next day.
Tropical Storm Hank originated out of an area of low pressure over the South China Sea in late September. Minimal convection was associated with the system and only light winds were recorded. Over the following days, the system gradually organized and by October 3, the JTWC issued a TCFA for the system. However, in post-storm analysis, it was found that Hank was already a tropical storm by this time. By the time the TCFA was issued, Hank reached its peak intensity with winds of 75 km/h (45 mph) before succumbing to strong wind shear. Late on October 3, Hank weakened to a tropical depression and was initially thought to have made landfall; however, satellite analysis showed that the center did not cross land until October 5, shortly before dissipating. There were no reports of damage in relation to the storm.
Forming out of an area of disturbed weather on October 13, Ivan gradually intensified into a typhoon as it tracked steadily to the west-northwest. On October 15, the storm underwent rapid intensification and reached an intensity corresponding to Category 5 status on the Saffir–Simpson Hurricane Scale. Late on October 17, Ivan reached its peak strength with winds of 295 km/h (185 mph) and a barometric pressure of 905 hPa (mbar). Shortly thereafter, the typhoon began to weaken as it approached the Philippines. Ivan eventually made landfall in northern Luzon with winds of 220 km/h (140 mph) on October 20 before weakening to a tropical storm the next day. The storm then curved northeastward and became extratropical on October 25, dissipating the following day. During its existence, Ivan was monitored by PAGASA and designated with the local name Narsing.
Although Ivan was a powerful storm at landfall, its effects were relatively minor compared to the storm's intensity; however, 14 people were killed during the storm and two others were listed as missing. Agricultural industries sustained the most severe damage, as thousands of animals drowned in the storm. Throughout the Philippines, damage amounted to $9.6 million (1997 USD; $13.1 million 2009 USD). A total of 1,779 homes were destroyed, 13,771 others were damaged and 4,600 hectares of farmland were flooded by the storm.
Typhoon Joan caused significant damage throughout the Marshall Islands. The most severe damage occurred on Anatahan where 37 homes were destroyed. Three people were injured during preparations for the storm when a wind gust blew a sheet of plywood into residents. Damages from the storm amounted to $200,000, mainly on Anatahan.
The tenth of eleven tropical cyclones to attain super typhoon intensity in the western North Pacific during 1997, Keith formed at low latitudes in the Marshall Islands. It was one of ten TCs which formed east of 160°E and south of 20°N — within the "El Niño". Keith was a recurving TC which passed between the Islands of Rota and Tinian (only 50 nmi/93 km
apart) on the west-bound leg of its recurving track. NEXRAD imagery from Guam indicated the eye wall cloud of Keith never touched land as it threaded the narrow channel between these two islands. As such, the Mariana Islands were spared the full force of Keith. Keith's compact wind and cloud structure were revealed by Guam's NEXRAD Equatorial westerly winds bounded by twin near-equatorial troughs preceded the formation of Keith and a Southern Hemisphere twin.
Typhoon Linda, after moving through the Philippines and the South China Sea, hit the Malay Peninsula on November 3. It restrengthened in the Bay of Bengal, but vertical shear caused Linda to dissipate on the 9th.
On 2 November, Linda hit the southern tip of Vietnam, the Ca Mau province, causing unprecedented havoc with 1,292 people being killed in Vietnam, most of which drowned at sea. Nearly 80,000 houses are reported as destroyed and almost 140,000 as badly damaged. Infrastructure (roads, schools and hospitals) also suffered heavily and huge swathes of rice paddy were swamped. The hardest hit provinces were Kien Giang, Ca Mau, Bac Lieu, Soc Trang, Tra Vinh, Ben Tre and Vung Tau. It was the worst typhoon to strike the area in 100 years. Damages from the storm amounted to VND 7 trillion (US$409 million).
Elsewhere in Thailand and the Philippines, Linda caused further deaths from flooding and heavy damage.
The final super typhoon of the year developed in the Central Pacific on November 28. It moved westward, strengthening into a tropical storm before crossing the International Date Line on December 7. Conditions were marginally favorable for development, and Paka remained a tropical storm until December 10, when it was able to become a typhoon. Five days later, Paka reached Super Typhoon strength, the eleventh of the year. The next day it crossed over Guam, and on December 18, Paka reached a peak of 185 mph winds. After causing major damage across the smaller Western Pacific island groups, Paka rapidly weakened and dissipated on December 22.
Typhoon Paka first impacted the Marshall Islands, where it dropped heavy rainfall and left $80 million in damage (1997 USD, $109 million 2009 USD). Later, it passed just north of Guam, where strong winds destroyed about 1,500 buildings and damaged 10,000 more; 5,000 people were left homeless, and the island experienced a complete power outage following the typhoon. Damage on the island totaled $500 million (1997 USD, $680 million 2009 USD), which warranted the retirement of its name. Paka also caused light damage in the Northern Mariana Islands, and overall the typhoon caused no reported fatalities.
The table on the right shows the Accumulated Cyclone Energy for each storm in the season. The ACE is, broadly speaking, a measure of the power of the typhoon multiplied by the length of time it existed for, so typhoons that lasted a long time (like Typhoon Paka) have higher ACEs. The total ACE for the 1997 season was 594.11, which is the highest ACE for any tropical cyclone season in recorded history. This was because 11 of the 33 storms in the season reached super typhoon status. ACE for Linda, Paka, and Oliwa only include ACE during the time they were in the Western Pacific Basin.
1997 storm names
Western North Pacific tropical cyclones were named by the Joint Typhoon Warning Center. The first storm of 1997 was named Hannah and the final one was named Mort.