1997 Pacific typhoon season
The 1997 Pacific typhoon season was a record-breaking season featuring eleven tropical cyclones reaching super typhoon intensity, tying the record with 1965 with the most intense tropical cyclones globally, and was the ninth and last consecutive year of above-average tropical cyclone activity that started in 1988. Its extremely high activity produced the highest ACE index ever recorded in a single tropical cyclone season. In addition, this season had ten Saffir-Simpson Category 5-equivalent tropical cyclones, the most ever recorded, even greater than the 2005 Atlantic hurricane season, and 2020 Atlantic hurricane season, for Category 4, which had nearly half of the amount. The 1997–98 El Niño event was a contributing factor to this unusually high activity. Despite this, the season produced an average number of tropical storms, spawning 28 tropical storms.
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. The first named storm, Hannah, developed on January 20 while the last named storm, Paka, dissipated on December 23. Tropical Storm Linda became the worst tropical cyclone to hit Vietnam, killing over 3,000 people.
The scope of this article is limited to the Pacific Ocean to the north of the equator between 100°E and 180th meridian. Within the northwestern Pacific Ocean, there are two agencies which assign names to tropical cyclones which can often result in a cyclone having two names. The Japan Meteorological Agency will name a tropical cyclone if it has 10-minute sustained wind speeds of at least anywhere in the basin, while the Philippine Atmospheric, Geophysical and Astronomical Services Administration assigns names to tropical cyclones which are active in the Philippine Area of Responsibility, located between 135°E and 115°E and between 5°N–25°N, regardless of whether or not a tropical cyclone has already been given a name by the JMA. Tropical depressions that are monitored by the United States' Joint Typhoon Warning Center are given a number with a "W" suffix.
Seasonal summary
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from:19/01/1997 till:24/01/1997 color:TD text:"Hannah"
from:12/04/1997 till:23/04/1997 color:VSTY text:"Isa"
from:22/04/1997 till:26/04/1997 color:TS text:"Jimmy"
from:06/05/1997 till:10/05/1997 color:TS text:"Kelly"
from:26/05/1997 till:30/05/1997 color:TS text:"Levi"
from:27/05/1997 till:01/06/1997 color:TY text:"Marie"
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from:22/06/1997 till:28/06/1997 color:TY text:"Peter"
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from:18/07/1997 till:31/07/1997 color:VSTY text:"Rosie"
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from:20/07/1997 till:02/08/1997 color:TS text:"Scott"
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from:25/07/1997 till:01/08/1997 color:TD text:"TD
from:29/07/1997 till:09/08/1997 color:TY text:"Tina"
from:30/07/1997 till:04/08/1997 color:ST text:"Victor"
from:06/08/1997 till:20/08/1997 color:VSTY text:"Winnie"
from:16/08/1997 till:22/08/1997 color:ST text:"Yule"
from:17/08/1997 till:18/08/1997 color:TD text:"16W"
from:20/08/1997 till:24/08/1997 color:ST text: "Zita"
from:21/08/1997 till:31/08/1997 color:TY text:"Amber"
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from:26/08/1997 till:04/09/1997 color:VSTY text:"Bing"
from:27/08/1997 till:27/08/1997 color:TD text:"TD"
from:27/08/1997 till:30/08/1997 color:TS text:"Cass"
from:03/09/1997 till:03/09/1997 color:TD text:"TD"
from:03/09/1997 till:16/09/1997 color:VSTY text:"Oliwa"
from:11/09/1997 till:19/09/1997 color:VSTY text:"David"
from:20/09/1997 till:24/09/1997 color:TD text:"Ella"
from:21/09/1997 till:27/09/1997 color:ST text:"Fritz"
from:23/09/1997 till:30/09/1997 color:VSTY text:"Ginger"
from:28/09/1997 till:04/10/1997 color:TD text:"Hank"
from:02/10/1997 till:08/10/1997 color:TD text:"26W"
from:13/10/1997 till:25/10/1997 color:VITY text:"Ivan"
from:13/10/1997 till:24/10/1997 color:VITY text:"Joan"
from:26/10/1997 till:08/11/1997 color:VITY text:"Keith"
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from:27/10/1997 till:29/10/1997 color:TD text:"TD"
from:31/10/1997 till:03/11/1997 color:ST text:"Linda"
from:09/11/1997 till:16/11/1997 color:TS text:"Mort"
from:11/11/1997 till:11/11/1997 color:TD text:"TD"
from:07/12/1997 till:23/12/1997 color:VSTY text:"Paka"
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from:01/01/1997 till:01/02/1997 text:January
from:01/02/1997 till:01/03/1997 text:February
from:01/03/1997 till:01/04/1997 text:March
from:01/04/1997 till:01/05/1997 text:April
from:01/05/1997 till:01/06/1997 text:May
from:01/06/1997 till:01/07/1997 text:June
from:01/07/1997 till:01/08/1997 text:July
from:01/08/1997 till:01/09/1997 text:August
from:01/09/1997 till:01/10/1997 text:September
from:01/10/1997 till:01/11/1997 text:October
from:01/11/1997 till:01/12/1997 text:November
from:01/12/1997 till:31/12/1997 text:December
The accumulated cyclone energy index for the 1997 Pacific typhoon season as calculated by Colorado State University using data from the Joint Typhoon Warning Center was 570.4 units, which is the highest ACE for a single season ever recorded. Broadly speaking, ACE is a measure of the power of a tropical or subtropical storm multiplied by the length of time it existed. It is only calculated for full advisories on specific tropical and subtropical systems reaching or exceeding wind speeds of.
The season was unusual and exceptional in the number of super typhoons that occurred in the basin. 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. Eleven typhoons reached winds of at least 135 knots. They were Isa, Nestor, Rosie, Winnie, Bing, Oliwa, Ginger, Ivan, Joan, Keith, and Paka. This was due to the 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. This is also due to the El Niño during that time, which tends to shift typhoon tracks east. 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.
Systems
Tropical Depression Hannah (Atring)
In early January, an area of convection developed along a near-equatorial trough 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.Near the end of its duration, the Philippine Atmospheric, Geophysical and Astronomical Services Administration began issuing warnings on Hannah when was a tropical depression; the institution named the storm Tropical Depression Atring. Hannah was not considered a tropical storm by the Japan Meteorological Agency. There were no reports of significant damage or injuries.
Typhoon Isa
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, as reported by the Joint Typhoon Warning Center; Japan Meteorological Agency reported maximum 10-min winds of. 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, the majority of it from crop damage. No deaths were reported.