Tropical cyclones in 1997

The year 1997 was regarded as one of the most intense tropical cyclone years on record, featuring a record 12 category 5-equivalent tropical cyclones, according to the Saffir–Simpson hurricane wind scale. The year also featured the second-highest amount of accumulated cyclone energy (ACE) on record, just behind 1992 and 2018. Throughout the year, 108 tropical cyclones have developed in bodies of water, commonly known as tropical cyclone basins. However, only 89 tropical cyclones were of those attaining 39 mph or greater, falling just below the long term average of 102 named systems. The most active basin was the Western Pacific, attaining an ACE amount of 571, the highest ever recorded in any season in any basin on record. The deadliest tropical cyclone was Severe Tropical Storm Linda (Openg). The costliest tropical cyclone was Super Typhoon Winnie (Ibiang), which set a record for having the largest eye on record. The most intense tropical cyclone was Hurricane Linda, peaking at 902 hPa/mbar. Typhoon Paka (Rubing), the longest-lived system, produced the fourth-highest ACE for a single tropical cyclone, just behind Typhoon Nancy (1961), Hurricane/Typhoon Ioke (2006), and Cyclone Freddy (2023). The accumulated cyclone energy (ACE) index for the 1997 (seven basins combined), as calculated by Colorado State University was 1,099.2 units.

Tropical cyclones are primarily monitored by a group of ten warning centres, which have been designated as a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC) by the World Meteorological Organization. These are the United States National Hurricane Center (NHC) and Central Pacific Hurricane Center, the Japan Meteorological Agency (JMA), the India Meteorological Department (IMD), Météo-France, Indonesia's Badan Meteorologi, Klimatologi, dan Geofisika, the Australian Bureau of Meteorology (BOM), Papua New Guinea's National Weather Service, the Fiji Meteorological Service (FMS) as well as New Zealand's MetService. Other notable warning centres include the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), the United States Joint Typhoon Warning Center (JTWC), and the Brazilian Navy Hydrographic Center.

Global conditions
In January 1997, satellites gathering information on water temperatures and sea level heights discovered an area of unusually warm water situated across the western half of the Pacific Ocean. About 150 m below the surface, water temperatures were about 3 °C (5.4 °F) above normal, signifying that an El Niño–Southern Oscillation (ENSO) event was beginning. By this time, the Scripps Institution of Oceanography had forecast that an ENSO was likely to take place during the latter half of 1997. Throughout February, water temperatures began increasing over much of the Pacific as well as in shallower waters off the coast of Peru. The above-average water temperatures covered an area roughly 11,000 km across, almost stretching from New Guinea to South America. By April, the ENSO became fully established; a column of warm water extended to the surface in the middle of the Pacific Ocean and water anomalies exceeded 5 °C (9 °F) about 150 m below the ocean surface. At the surface off the coast of Peru, water temperatures averaged 3 °C (5.4 °F) above normal.

Exceedingly warm waters became apparent by May, especially off the coast of South America where anomalies were reaching 7 °C (12.6 °F) above normal. Further north, sea surface temperatures along the Pacific coast of North America were increasing, with a large pool of water being 3 °C (5.4 °F) above normal. By September 1997, the ENSO became very powerful, with surface temperatures between South America and the International Date Line averaging 2–4 °C (3.6–7.2 °F) above normal, roughly a quarter of the planet's diameter. Additionally, waters along the Pacific coast of North America continued to expand, now stretching from Alaska to southern Mexico. A contrasting area of abnormally cool waters took shape near the coast of Australia by September as well, with waters 150 m below the surface averaging 4 °C (7.2 °F) below normal. Along the Pacific coast of the Americas, the volume of 21 to 30 C water was roughly 30 times greater than that of all the water in the Great Lakes combined. The extra heat energy created by this anomaly was also about 93 times more than the energy produced by fossil fuels in the United States during 1995.

North Atlantic Ocean
The Atlantic hurricane season officially began on June 1, and an unnamed subtropical storm developed on the same day. Only nine tropical depressions formed. Eight of the depressions attained tropical storm status, making 1997 the least active Atlantic hurricane season in the ongoing above-average era of tropical cyclogenesis, which began in 1995. Just three of these systems attained hurricane status and only one tropical cyclone intensified into a major hurricane, which was below the 1981–2010 average of three per season. Only Danny made landfall at hurricane strength during the season, although Hurricane Erika and Tropical Storm Grace also caused damage and fatalities. Those three cyclones collectively caused 12 deaths and $111.46 million in damage. The last storm of the season, Tropical Storm Grace, dissipated on October 17, over a month before the official end of the season on November 30.

The 1997 Atlantic hurricane season had a very active beginning. In June, two tropical cyclones developed – the unnoticed subtropical storm and Tropical Storm Ana. An unusual four tropical cyclones formed in the month of July, three of which reached tropical storm intensity, and two of them became hurricanes. Despite the active start, the other months of the season featured record low activity, especially in August and September, both of which combined produced only one tropical cyclone. As a result of the active start and subsequent lack of activity, it showed that early season activity has no correlation to the entire season. Further, this marked the first occurrence of no tropical cyclogenesis in August since 1961, and the most recent instance of no activity in that month until 2022. The lone tropical cyclone during the period was Hurricane Erika, which developed on September 3. In October, two short-lived tropical cyclones developed, Fabian and Grace. Tropical cyclogenesis ceased after Grace transitioned into an extratropical cyclone on October 17. The season's activity was reflected with a low accumulated cyclone energy (ACE) rating of 41. ACE is, broadly speaking, a measure of the power of the hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, have high ACEs. It is only calculated for full advisories on tropical systems at or exceeding 39 mph (63 km/h), which is the threshold for tropical storm strength.

Eastern & Central Pacific Oceans
It was a very active hurricane season. With hundreds of deaths and hundreds of millions of dollars in damage, this was one of the deadliest and costliest Pacific hurricane seasons on record. The season produced 17 named storms, which was a little above normal. The average number of named storms per year is 15. The 1997 season also had 9 hurricanes, compared to the average of 8. There were also 7 major hurricanes compared to the average of 4. This was due to the exceptionally strong ongoing El Niño event. Several storms impacted land. The first was Tropical Storm Andres which killed four people and left another two missing. In August, Tropical Storm Ignacio took an unusual path through the basin, resulting in its extratropical remnants causing minimal damage throughout the Pacific Northwest and California. Linda became the most intense east Pacific hurricane in recorded history, a record it maintained until it was surpassed by Hurricane Patricia in 2015. Although it never made landfall, it produced large surf in Southern California and as a result, five people had to be rescued. Hurricane Nora caused flooding and damage in the Southwestern United States, while Olaf made two landfalls and caused eighteen deaths and several other people were reported missing. Hurricane Pauline killed several hundred people and caused record damage in southeastern Mexico. In addition, Super Typhoons Oliwa and Paka originated in the region before crossing the International Date Line and causing significant damage in the western Pacific. There were also two Category 5 hurricanes: Linda and Guillermo. The National Hurricane Center uses accumulated cyclone energy (ACE) to rank hurricane seasons as above-normal, near-normal, and below-normal. The total ACE of this season is 160*104 kt2 in the east Pacific proper, which qualifies this season as above-normal.

Western Pacific Ocean
It was a record-breaking season featuring eleven tropical cyclones reaching super typhoon intensity, tying the record with 1965 with the most violent tropical cyclones globally, and was the ninth and last consecutive year of above-average tropical cyclone activity that started in 1989. Its extremely high activity produced a total of 570 ACE index, which is the highest ever index 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, 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 twenty-nine tropical storms. 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

North Indian Ocean
On May 13, a near-equatorial trough developed. The poorly organized system slowly tracked towards the north-northwest. The following day, deep convection consolidated around the center of circulation and the Joint Typhoon Warning Center (JTWC) classified the system as Tropical Cyclone 01B. Favorable upper-level conditions and good outflow allowed the storm to intensify. Shortly after, the cyclone attained tropical storm-force winds and turned towards the northeast. While gradually increasing in forward motion, the storm continued to strengthen. On May 17, the cyclone attained winds of 120 km/h (75 km/h), equivalent to a Category 1 hurricane on the Saffir–Simpson scale. By May 18 an eye developed and the storm reached its peak intensity with winds of 215 km/h before making landfall near Chittagong. After landfall, the storm rapidly tracked northeastward inland and dissipated early on May 20. It caused significant damage and 67 fatalities. On September 19, a tropical depression formed from an area of disturbed weather in the western Bay of Bengal. It drifted northwestward towards the Indian coastline, but a mid-latitude trough pulled it northeastward, The depression strengthened to a tropical storm on the 24th, and it reached cyclone strength while paralleling the Indian coastline on 26th. It made landfall in Bangladesh on the 27th, and dissipated shortly thereafter. Tropical Cyclone 2B was responsible for 51 fatalities and left an additional 137 people missing.

Typhoon Linda killed 30 while crossing the Malay Peninsula, emerged into the Bay of Bengal on November 4. It continued westward, reaching cyclone strength again, but vertical shear caused it to dissipate on the 9th. In southern Thailand, 30 people were killed and 102 others were listed as missing as a result of the storm. Linda damaged at least 100 homes and sank 30 ships in the region. An estimated 6,400,000 m2 of farmland were destroyed by Linda. A broad trough of low pressure formed into a tropical depression on November 4 in the central Arabian Sea. It moved westward, slowly intensifying into a tropical storm on the 8th. Vertical shear weakened it to a depression later that day, but on the 9th, just before making landfall on eastern Somalia, it restrengthened to a tropical storm. Tropical Storm Three dissipated on the 10th without causing any reported damage.

January–June
It was the longest on record, with both an unusually early start and unusually late ending. Most activity was from November through February. According to the Météo-France office (MFR) at Réunion, there were 21 tropical disturbances, 14 of which intensified into tropical depressions. There were 12 named storms, beginning with Antoinette and proceeding sequentially until Lisette. In addition, the Joint Typhoon Warning Center also warned on storms in the region, which identified five other tropical storms. Five of the storms attained tropical cyclone status, or with 10–minute maximum sustained winds of at least 120 km/h; of these, three strengthened further into intense tropical cyclones, with Daniella and Helinda tied for strongest storm of the season.

In August, a tropical depression developed in the south-west Indian Ocean for the first time 27 years, and a month later, a rare September tropical disturbance formed. The first named storm, Antoinette, was the first of several to originate in the neighboring Australian basin, or east of 90° E; the subsequent two named storms also formed in the Australian region. In early December, Cyclone Daniella likely developed out of the remnants of previous Tropical Storm Chantelle. After reaching peak 10–minute winds of 185 km/h, Daniella weakened and passed just southwest of Mauritius; there, the storm left heavy crop damage and indirectly caused three deaths. In early January, Tropical Storm Fabriola was the first in a succession of three storms to move over Madagascar. The next – Cyclone Gretelle – killed 152 people when it struck southeastern Madagascar. Between January and February, Cyclone Pancho-Helinda lasted about 20 days between both the Australian and south-west Indian basins. Also in February, Tropical Storm Josie killed 36 people in western Madagascar after causing severe flooding. The final named storm was Tropical Storm Lisette, which dissipated on March 3 after striking Mozambique, killing three people. Despite the early end to the named storms, there were two additional disturbances, one of which became the first July tropical depression in 25 years.

July–December
No storms or tropical depressions had formed during July and December 1997.

March
March was a well below-average, featuring three systems. All of them have been named. The month began in the South Pacific Ocean with Cyclone Gavin, which recently affected the island nations of Tuvalu and Wallis and Futuna, killing 18 people. After Gavin dissipated, Cyclone Hina formed on 11 March, causing more than $15.2 million in damage and was indirectly responsible for one death as it affected Tuvalu, Wallis and Futuna, and Tonga. The worst impact of the system was recorded on Tongatapu and 'Eua, which are the southernmost islands of the Kingdom of Tonga. Cyclone Justin in the Australian region had a long and erratic track, causing widespread damage in Queensland and Papua New Guinea, killing 34 people in total.

April
April was also well below-average, featuring three systems. All of them have been named. Typhoon Isa in the Western Pacific Ocean, became the first of a record eleven super typhoons to occur during the basin, leaving behind $1 million.

Global effects
There are a total of nine tropical cyclone basins, seven are seasonal and two are non-seasonal, thus all eight basins except the Mediterranean are active. In this table, data from all these basins are added.