Typhoon Isa

Last updated
Typhoon Isa
Typhoon (JMA  scale)
Category 5-equivalent super typhoon (SSHWS)
Isa 1997-04-20 0500Z.png
Typhoon Isa at peak intensity
FormedApril 12, 1997
DissipatedApril 24, 1997
(Extratropical after April 23)
Highest winds 10-minute sustained: 155 km/h (100 mph)
1-minute sustained: 270 km/h (165 mph)
Lowest pressure940 hPa (mbar); 27.76 inHg
FatalitiesNone reported
Damage$1 million (1997 USD)
Areas affected Pohnpei, Guam, Rota
Part of the 1997 Pacific typhoon season

Typhoon Isa was the first of a record eleven super typhoons to occur during the 1997 Pacific typhoon season. The second tropical cyclone of the season, 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.

Contents

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, $1.61 million2021 USD), the majority of it from crop damage. No deaths were reported.

Meteorological history

Map plotting the storm's track and intensity, according to the Saffir-Simpson scale

Map key
Saffir-Simpson scale
.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}
.mw-parser-output .legend{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .legend-color{display:inline-block;min-width:1.25em;height:1.25em;line-height:1.25;margin:1px 0;text-align:center;border:1px solid black;background-color:transparent;color:black}.mw-parser-output .legend-text{}
Tropical depression (<=38 mph, <=62 km/h)

Tropical storm (39-73 mph, 63-118 km/h)

Category 1 (74-95 mph, 119-153 km/h)

Category 2 (96-110 mph, 154-177 km/h)

Category 3 (111-129 mph, 178-208 km/h)

Category 4 (130-156 mph, 209-251 km/h)

Category 5 (>=157 mph, >=252 km/h)

Unknown
Storm type
Tropical cyclone
Subtropical cyclone
Extratropical cyclone / Remnant low / Tropical disturbance / Monsoon depression Isa 1997 track.png
Map plotting the storm's track and intensity, according to the Saffir–Simpson scale
Map key
  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown
Storm type
ArrowUp.svg Extratropical cyclone / Remnant low / Tropical disturbance / Monsoon depression

In early April, the monsoon trough established itself across Micronesia near the equator. An area of convection within the trough developed in the Caroline Islands on April 9, and resembled the characteristics of a monsoon depression. Shortly thereafter, a large, yet weak low-level circulation formed within the system. The system drifted erratically for several days as it slowly organized; the system underwent several cycles of developing and losing convection. On April 11, the system maintained a persistent area of well-organized deep convection, and subsequent to an increase in upper-level outflow, the Joint Typhoon Warning Center (JTWC) classified the system as Tropical Depression 02W at 1800 UTC on April 11. Strong influence from the monsoonal westerlies left the depression drifting and slowly executing a loop to the northwest. Based on sufficient satellite classifications, JTWC upgraded the depression to Tropical Storm Isa early on April 12 while it was located 105 km (65 mi) of Pohnpei. [1] The Japan Meteorological Agency (JMA) simultaneously classified the system as a tropical depression, and upgraded it to a tropical storm early on April 13. [2]

With the subtropical ridge to its north, [3] Isa tracked to the north and gradually curved to the west. It slowly intensified, due to it being a large tropical cyclone, and late on April 13 JTWC upgraded the storm to typhoon status; [1] at the same time, JMA continued to assess Isa as a minimal tropical storm, and did not upgrade it to a typhoon until April 16. [2] Isa maintained a nearly due-westward movement, although tropical cyclone prediction models anticipated a quick turn to the north. The JTWC recognized the northward model bias, which was described as under-analyzing the strength of the subtropical ridge. By April 16, the typhoon attained the equivalence of a Category 3 tropical cyclone on the Saffir-Simpson Hurricane Scale, and despite a potential threat to Guam the typhoon remained 260 km (160 mi) south of the island. It gradually curved to the north, and on April 20 JTWC classified Super Typhoon Isa as reaching peak 1-min winds of 270 km/h (165 mph). At this point, Isa became an annular typhoon, with a large eye and a lack of spiralform rainbands, while moving nearly due northward, through a weakness in the subtropical ridge. [1] Simultaneously, JMA assessed the typhoon as attaining peak 10-min winds of 155 km/h (100 mph). [2]

Shortly after peaking in intensity, Isa began to weaken, and by April 21 it dropped below "super typhoon" status. It accelerated to the northeast under the flow of the mid-latitudes, and the typhoon weakened more rapidly; [1] JMA downgraded Isa to a tropical storm on April 22, [2] which was followed suit by the JTWC the next day as upper-level wind shear increased. At 0600 UTC on April 23, the JTWC issued the last advisory on the system, [1] and the next day JMA classified Isa dissipated as it became absorbed by a cloud band from a large extratropical cyclone to the east of Japan. [1] [2]

Impact

Typhoon Isa visible from Guam NEXRAD Isa from Guam Radar.jpg
Typhoon Isa visible from Guam NEXRAD

Isa first affected Pohnpei as a tropical storm on April 12. While passing near the island, the storm produced moderate winds across the island, peaking at 95 km/h (60 mph). The winds downed several trees and tree limbs which destroyed 40% of the island's power lines. A few buildings reported roof damage. About 15% of the crops on Pohnpei were damaged, including losses to the banana and breadfruit crops. [4] After the passage of the typhoon, President of the Federated States of Micronesia Jacob Nena declared Pohnpei as a major disaster area due to the damage from Typhoon Isa and subsequent flooding; on April 20 heavy rainfall caused widespread mudslides and 19 fatalities on the island, though they were not related to Isa. [4] [5]

In Guam, the threat of Typhoon Isa postponed a flight from Guam to Honolulu, Hawaii for 48 hours. The flight was the last in Operation Pacific Haven  [ de ], which was a multimillion-dollar humanitarian effort to transport more than 6,600  Kurds in a political asylum to the mainland of the United States. [6] [7] The threat of the typhoon also canceled the first round of the Omega Tour golf event, which was the second professional golf tournament in the island's history. [8] [9] Though Typhoon Isa passed well to the south of Guam, one of its outer rainbands stalled across the island, which dropped heavy rainfall of 15–25 cm (6–10 in) across the island. The rainfall was welcome as it occurred during the dry season, [1] and largely contributed to rainfall at the Guam International Airport being 45% above normal from the period between January through April. [10] The rainband also produced wind gusts that reached 86 km/h (53 mph) at the island's Naval Air Station; the winds resulted in sporadic power outages across the island. The typhoon caused some light damage to buildings, particularly on the south side of the island. The combination of winds and sea salt caused damage to the island's tomato, okra, cucumber, and soy bean crops. [4]

Typhoon Isa later dropped light rainfall on the island of Rota. [10] Across its path, damage from the storm totaled over $1 million (1997 USD, $1.61 million2021 USD). No deaths or injuries were reported. [4]

See also

Related Research Articles

Typhoon Paka Category 5 Pacific hurricane and typhoon in 1997

Typhoon Paka, known in the Philippines as Typhoon Rubing, was the last tropical cyclone of the 1997 Pacific hurricane and typhoon season, and was among the strongest Pacific typhoons in the month of December. Paka, which is the Hawaiian name for Pat, developed on November 28 from a trough well to the southwest of Hawaii. The storm tracked generally westward for much of its duration, and on December 7 it crossed into the western Pacific Ocean. Much of its track was characterized by fluctuations in intensity, and on December 10 the cyclone attained typhoon status as it crossed the Marshall Islands. On December 16, Paka struck Guam and Rota with winds of 230 km/h (145 mph), and it strengthened further to reach peak winds on December 18 over open waters as the final super typhoon of the year. Subsequently, it underwent a steady weakening trend, and on December 23 Paka dissipated.

2004 Pacific typhoon season

The 2004 Pacific typhoon season was an extremely active season that featured the second-highest ACE ever recorded in a single season, second only to 1997, which featured 29 named storms, nineteen typhoons, and six super typhoons. It was an event in the annual cycle of tropical cyclone formation, in which tropical cyclones form in the western Pacific Ocean. The season ran throughout 2004, though most tropical cyclones typically develop between May and October. The season's first named storm and also the first typhoon, Sudal, developed on April 4, later was reached typhoon status two days later, and became the first super typhoon of the year three days later. The season's last named storm, Noru, dissipated on December 21.

2003 Pacific typhoon season Period of formation of tropical cyclones in the Western Pacific Ocean in 2003

The 2003 Pacific typhoon season was a slightly below average yearlong period of tropical cyclogenesis exhibiting the development of 45 tropical depressions, of which 21 became named storms; of those, 14 became typhoons. Though every month with the exception of February and March featured tropical activity, most storms developed from May through October. During the season, tropical cyclones affected the Philippines, Japan, China, the Korean Peninsula, Indochina, and various islands in the western Pacific.

2002 Pacific typhoon season Tropical cyclone season in the Western Pacific Ocean

The 2002 Pacific typhoon season was a slightly above average Pacific typhoon season, producing twenty-six named storms, fifteen becoming typhoons, and eight super typhoons. It was an event in the annual cycle of tropical cyclone formation, in which tropical cyclones form in the western Pacific Ocean. The season ran throughout 2002, though most tropical cyclones typically develop between May and October. The season's first named storm, Tapah, developed on January 11, while the season's last named storm, Pongsona, dissipated on December 11. The season's first typhoon, Mitag, reached typhoon status on March 1, and became the first super typhoon of the year four days later.

1999 Pacific typhoon season Typhoon season in the Pacific Ocean

The 1999 Pacific typhoon season was the last Pacific typhoon season to use English names as storm names. It was a very inactive season, featuring the lowest number of typhoons on record, five. It had 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.

1997 Pacific typhoon season

The 1997 Pacific typhoon season was a record-breaking season featuring 11 tropical cyclones reaching super typhoon intensity, tying the record with 1965 with the most violent tropical cyclones globally. It 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.

1988 Pacific typhoon season

The 1988 Pacific typhoon season had no official bounds; it ran year-round in 1988, 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. Tropical Storms formed in the entire west Pacific basin were assigned a name by the Joint Typhoon Warning Center. 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.

1987 Pacific typhoon season

The 1987 Pacific typhoon season has no official bounds; it ran year-round in 1987, 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. Tropical storms formed in the entire west pacific basin were assigned a name by the Joint Typhoon Warning Center. 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.

Typhoon Pongsona Pacific typhoon in 2002

Typhoon Pongsona was the last typhoon of the 2002 Pacific typhoon season, and was the second costliest United States disaster in 2002, only behind Hurricane Lili. The name "Pongsona" was contributed by North Korea for the Pacific tropical cyclone list and is the Korean name for the garden balsam. Pongsona developed out of an area of disturbed weather on December 2, and steadily intensified to reach typhoon status on December 5. On December 8 it passed through Guam and the Northern Mariana Islands while near its peak winds of 175 km/h. It ultimately turned to the northeast, weakened, and became extratropical on December 11. Typhoon Pongsona produced strong wind gusts peaking at 290 km/h, which left the entire island of Guam without power and destroyed about 1,300 houses. With strong building standards and experience from repeated typhoon strikes, there were no fatalities directly related to Pongsona, although there was one indirect death from flying glass. Damage on the island totaled over $730 million, making Pongsona among the five costliest typhoons on the island. The typhoon also caused Extreme damage on Rota and elsewhere in the Northern Mariana Islands, and as a result of its impact the name was retired.

Typhoon Chataan Pacific typhoon in 2002

Typhoon Chataan, known in the Philippines as Typhoon Gloria, was the deadliest natural disaster in the history of Chuuk, a state in the Federated States of Micronesia (FSM). The typhoon formed on June 28, 2002, near the FSM, and for several days it meandered while producing heavy rainfall across the region. On Chuuk, the highest 24-hour precipitation total was 506 mm (19.9 in), which was greater than the average monthly total. The rain produced floods up to 1.5 m (4.9 ft) deep, causing landslides across the island that killed 47 people. There was also one death on nearby Pohnpei, and damage in the FSM totaled over $100 million.

Typhoon Angela (1989) Pacific typhoon in 1989

Super Typhoon Angela, known in the Philippines as Typhoon Rubing, was an intense tropical cyclone that formed in late September 1989. The storm developed from a tropical disturbance in the monsoon trough and moved generally westward throughout its duration. The storm ultimately peaked in intensity as a super typhoon and struck northern Luzon in the Philippines. After weakening and traversing the South China Sea, Angela bypassed Hainan to the south and struck Vietnam before dissipating. The storm caused severe damage and 119 fatalities in the Philippines. Thousands of houses were damaged, and hundreds of thousands of residents were impacted by the typhoon. Monetary damage is placed at $8 million.

Typhoon Roy Pacific typhoon in 1988

Typhoon Roy, known in the Philippines as Typhoon Asiang, was the second-most intense January tropical cyclone on record in the Western Pacific basin. Forming out of an area of disturbed weather on January 7, 1988, Roy quickly intensified as it moved through the Marshall Islands. By January 9, the storm intensified into a typhoon and attained its peak intensity the following day. At its peak, sustained winds reached 215 km/h (135 mph). Slight weakening took place before the storm moved through the Mariana Islands. Continuing westward, the system eventually struck the Philippines as a minimal typhoon before dissipating over the South China Sea on January 19.

Typhoon Keith

Typhoon Keith was the tenth of a record eleven super typhoons to develop during the unusually intense 1997 Pacific typhoon season. Originating from a near-equatorial trough on October 26, the precursor depression to Keith slowly organized into a tropical storm. After two days of gradual strengthening, the storm underwent a period of rapid intensification on October 30 as winds increased to 195 km/h (120 mph). On November 1, the storm further intensified into a super typhoon and later attained peak winds of 285 km/h (180 mph). The following day, the powerful storm passed between Rota and Tinian in the Northern Mariana Islands. After fluctuating in strength over the following few days, a steady weakening trend established itself by November 5 as the typhoon accelerated towards the northeast. On October 8, Keith transitioned into an extratropical cyclone and was last noted early the following day near the International Dateline.

Typhoon Gay (1992) Pacific typhoon in 1992

Typhoon Gay, known in the Philippines as Typhoon Seniang, was the strongest and longest-lasting storm of the 1992 Pacific typhoon season and most intense globally in 1992. It formed on November 14 near the International Date Line from a monsoon trough, which also spawned two other systems. Typhoon Gay later moved through the Marshall Islands as an intensifying typhoon, and after passing through the country it reached its peak intensity over open waters. The Joint Typhoon Warning Center (JTWC) estimated peak winds of 295 km/h (185 mph) and a minimum barometric pressure of 872 mb (25.8 inHg). However, the Japan Meteorological Agency (JMA), which is the official warning center in the western Pacific, estimated winds of 205 km/h (125 mph), with a pressure of 900 mbar (27 inHg). Gay weakened rapidly after peaking because of interaction with another typhoon, and it struck Guam with winds of 160 km/h (100 mph) on November 23. The typhoon briefly re-intensified before weakening and becoming extratropical south of Japan on November 30.

Typhoon Kujira (2003) Category 4 Pacific typhoon in 2003

Typhoon Kujira, known in the Philippines as Typhoon Amang, was a long-lived tropical cyclone that lasted for 16 days affected the island nations of Micronesia, Taiwan, and Japan in April 2003, as well as the earliest typhoon in a calendar year to ever make landfall on the latter. Forming from a broad area of disturbed weather as a tropical depression on April 9 well removed from any landmasses, Kujira quickly intensified in its early stages, and was upgraded to a tropical storm just two days after cyclogenesis. Strengthening slowed afterwards, though the storm attained typhoon intensity on April 14. Intensification continued and late on April 15, Kujira reached its peak intensity with winds of 165 km/h (105 mph) and a minimum barometric pressure of 930 mbar. Following peak intensity, Kujira began to track northwest and oscillate in strength, cresting an additional two times in intensity. On April 21, the typhoon was downgraded to tropical storm intensity and began to track erratically for several days east of Taiwan. However, on April 24, Kujira resumed a northward track and begin to weaken, and on April 24 was downgraded to tropical depression strength as it made landfall on Kyushu. Following landfall Kujira transitioned into an extratropical cyclone and continued to persist before these extratropical remnants crossed the International Dateline towards the end of April 2003.

Typhoon Yuri (1991) Pacific typhoon in 1991

Super Typhoon Yuri was the most intense tropical cyclone in 1991 In terms of minimum central pressure. The nineteenth typhoon and final super typhoon of the 1991 Pacific typhoon season, Yuri was a tropical disturbance that strengthened into a tropical depression on November 22 in the Philippine Sea. Moving rather slowly at first, the system continued to intensify, and was given the name Yuri. It had become a severe tropical storm about 1,480 kilometers east of Truk Island and took on a west-northwestward track at 22 km/h. Typhoon intensity was attained that night when Yuri was 1,050 km. Yuri turned more to the west on 26 November and reached peak intensity the following morning packing winds of over 220 km/h near its centre. Moving northwestwards at 30 km/h, Yuri passed 140 km to the south-southwest of Guam on the evening of November 27. After recurving November 29, Yuri accelerated northeastwards on November 30 and weakened to a severe tropical storm that night. By the morning of December 1, it had degenerated into a tropical storm about a few hundred kilometers east-northeast of Iwo Jima. Extratropical transition was completed soon afterward, and the storm's remnants persisted until December 3.

Typhoon Mitag (2002) Category 5 Pacific typhoon in 2002

Typhoon Mitag, known in the Philippines as Typhoon Basyang, was the first super typhoon on record in the month of March. The second storm of the 2002 Pacific typhoon season, Mitag developed from a trough near the equator on February 25 near the Federated States of Micronesia (FSM). It moved westward through the archipelago and intensified into a typhoon before passing near Yap on March 2. High winds and heavy rainfall affected the state, resulting in an islandwide power outage and destroying hundreds of houses. Mitag caused severe crop damage that resulted in food shortages. The rainfall and storm surge flooded much of the coastline as well as Yap's capital, Colonia. Damage totaled $150 million, mostly from crop damage. There was one death related to the storm's aftermath.

Typhoon Lupit (2003) Category 5 Pacific super typhoon in 2003

Typhoon Lupit, known in the Philippines as Typhoon Yoyoy, destroyed the food supply in several small islands in Yap State in the Federated States of Micronesia (FSM). It formed on November 18, 2003, from the monsoon trough to the west of the Marshall Islands. Early in its duration, it moved generally to the west or west-southwest. On November 21, the depression intensified into Tropical Storm Lupit, the 21st storm named by the Japan Meteorological Agency of the 2003 Pacific typhoon season. Two days later, it strengthened into a typhoon and developed an eye. Lupit later began a prolonged movement to the northwest, during which it passed near several islands in Yap State. The typhoon reached peak intensity on November 26, with peak 10‑minute sustained winds of 185 km/h (115 mph). It later weakened due to increasing wind shear and drier air, and after recurving to the northeast, Lupit became extratropical south of Japan on December 2.

Typhoon Yancy (1990) Pacific typhoon in 1990

Typhoon Yancy, known as Typhoon Gading in the Philippines, was the second-deadliest typhoon of the 1990 Pacific typhoon season, after Typhoon Mike.

Typhoon Dolphin (2015) Pacific typhoon in 2015

Typhoon Dolphin was a powerful tropical cyclone that produced the first typhoon-force winds on Guam since Typhoon Pongsona in 2002. The seventh named storm of the 2015 Pacific typhoon season, Dolphin formed on May 6 in the vicinity of the Federated States of Micronesia (FSM). Moving eastward at first, the storm slowly organized before beginning a north and west-northwest trajectory. Dolphin intensified into a typhoon before passing between Guam and Rota on May 15, producing typhoon-force winds on both islands. It later rapidly intensified as it curved to the north. The American-based Joint Typhoon Warning Center (JTWC) designated Dolphin as a super typhoon, while the Japan Meteorological Agency (JMA) estimated 10 minute sustained winds of 185 km/h (115 mph). Dolphin turned to the northeast and weakened, becoming extratropical on May 20 and exiting the western Pacific basin on May 24.

References

  1. 1 2 3 4 5 6 7 Joint Typhoon Warning Center (1999). "Super Typhoon Isa (02W) ATCR". Archived from the original on 2011-06-07. Retrieved 2007-04-25.
  2. 1 2 3 4 5 Japan Meteorological Agency (1997). "1997 Western Pacific Best Track". Archived from the original on 2007-09-29. Retrieved 2007-04-15.
  3. Joint Typhoon Warning Center (1999). "Tropical Storm Jimmy (03W) ATCR". Archived from the original on 2011-06-07. Retrieved 2007-04-20.
  4. 1 2 3 4 National Climatic Data Center (1997). "Event Report for Guam". Archived from the original on 2008-05-22. Retrieved 2007-04-26.
  5. Federated States of Micronesia Information Service (1997-04-25). "Nena Declared Pohnpei Disaster, Asked President Clinton Likewise" . Retrieved 2007-04-26.
  6. Staff Writer (1997-04-16). "Storm delays last flight of 300 Kurds from Guam". Honolulu Star-Bulletin. Archived from the original on 2007-02-11. Retrieved 2007-04-26.
  7. Office of the Assistant Secretary of Defense (Public Affairs) (1997-04-15). "Operation Pacific Haven Wraps Up Humanitarian Efforts". U.S. Department of Defense. Retrieved 2007-04-26.
  8. Agence France Presse (1997-04-16). "Typhoon Isa looks likely to bring havoc to the start".
  9. Agence France Presse (1997-04-18). "China's Wu Xiangbing and Taiwan's Tsai Chi-huang over".
  10. 1 2 Alan C. Hilton (1998). "Pacific ENSO Update - 2nd Quarter 1997 - Vol. 3 No. 2". National Oceanic and Atmospheric Administration.