The 1997–1998 El Niño was regarded as one of the most powerful
El Niño–Southern Oscillation
El Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea te ...
events in recorded history, resulting in widespread droughts, flooding and other natural disasters across the globe. It caused an estimated 16% of the world's reef systems to die, and temporarily warmed air temperature by compared to the usual increase of associated with El Niño events.
It led to a severe outbreak of
Rift Valley fever after
extreme rainfall in north-eastern Kenya and southern Somalia.
It also led to record rainfalls in California during the water season of 1997–98 and one of Indonesia's worst droughts on record. 1998 ultimately became the warmest year in recorded history (up until then).
Meteorological progression

In January 1997, probes gathering information on deep water temperatures discovered an area of unusually warm water, centered around 150 meters depth, across the western half of the
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...
. About below the surface, water temperatures were about 3 °C (5.4 °F) above normal, signifying that an
El Niño-Southern Oscillation
EL, El or el may refer to:
Religion
* El (deity), a Semitic word for "God"
People
* EL (rapper) (born 1983), stage name of Elorm Adablah, a Ghanaian rapper and sound engineer
* El DeBarge, music artist
* El Franco Lee (1949–2016), American ...
(ENSO) event was beginning. By this time, the
Scripps Institution of Oceanography
The Scripps Institution of Oceanography (sometimes referred to as SIO, Scripps Oceanography, or Scripps) in San Diego, California, US founded in 1903, is one of the oldest and largest centers for ocean and Earth science research, public servi ...
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
, image_flag = Flag of Peru.svg
, image_coat = Escudo nacional del Perú.svg
, other_symbol = Great Seal of the State
, other_symbol_type = Seal (emblem), National seal
, national_motto = "Fi ...
. The above-average water temperatures covered an area roughly across, almost stretching from
New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...
to
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...
. 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 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 Dateline
The International Date Line (IDL) is an internationally accepted demarcation on the surface of Earth, running between the South and North Poles and serving as the boundary between one calendar day and the next. It passes through the Pacific ...
averaging 2-4 °C (3.6-7.2 °F) above normal, roughly a quarter of the planet's circumference. Additionally, the band of warmth along the Pacific coast of North America continued to expand, now stretching from
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S ...
to southern
Mexico
Mexico ( Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guate ...
. A contrasting area of abnormally cool waters took shape near the coast of
Australia by September as well, with waters below the surface averaging 4 °C (7.2 °F) below normal. Along the Pacific coast of the
Americas, the volume of water was roughly 30 times greater than that of all the water in the
Great Lakes
The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five la ...
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.
By January 1998, sea surface temperatures off the coast of Peru continued to increase, reaching 11 °C (19.8 °F) above average. However, the region of cooler than average water in the western Pacific expanded, signifying that a La Niña would take shape in the latter part of 1998. Just two months later, the extent of above-average water temperatures sharply decreased as the El Niño weakened. The 1997–98 ENSO event finally ended during May 1998 as below-average water temperatures extended across much of the Pacific.
Effects on tropical cyclone activity
The 1997–98 El Niño Event had various effects on
tropical cyclone
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Dep ...
activity around the world, with more tropical cyclones than average occurring in the Pacific basins. This included the Southern Pacific basin between 160°E and 120°W, where 16 tropical cyclones in the South Pacific were observed during the
1997–98 season compared to an average of around 8.
The area where most of the tropical cyclones developed was shifted eastwards, with parts of the
Cook Islands
)
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, capital = Avarua
, coordinates =
, largest_city = Avarua
, official_languages =
, langu ...
and
French Polynesia
)Territorial motto: ( en, "Great Tahiti of the Golden Haze")
, anthem =
, song_type = Regional anthem
, song = "Ia Ora 'O Tahiti Nui"
, image_map = French Polynesia on the globe (French Polynesia centered).svg
, map_alt = Location of French ...
impacted as a result.
In the West Pacific basin, the season saw a record of 11
super typhoons, with 10 of them reaching
Category 5 intensity. In the east Pacific basin, the
1997 season featured two Category 5 hurricanes,
Guillermo
Guillermo () is the Spanish form of the male given name William. The name is also commonly shortened to 'Guille' or, in Latin America, to nickname 'Memo'. People
* Guillermo Amor (born 1967), Spanish football manager and former player
* Guillermo ...
and
Linda, the latter of which was the strongest on record before
Patricia
Patricia is a female given name of Latin origin. Derived from the Latin word ''patrician'', meaning "noble"; it is the feminine form of the masculine given name Patrick. The name Patricia was the second most common female name in the United State ...
took that title during the
2015 season. The North Pacific basin broke the record for having the most tropical cyclones reaching Category 4 and 5 intensities with 17 that season. However, the 2015 season surpassed it with 21 tropical cyclones during the
2014–16 El Niño event.
See also
*
El Niño
El Niño (; ; ) is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (approximately between the International Date ...
**
1982–1983 El Niño event
__NOTOC__
Year 198 (CXCVIII) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Sergius and Gallus (or, less frequently, year 951 ''Ab u ...
**
2014–2016 El Niño event
The 2014–2016 El Niño was a warming of the eastern equatorial Pacific Ocean that resulted in unusually warm waters developing between the coast of South America and the International Date Line. These unusually warm waters influenced the world' ...
*
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-roun ...
*
1997 Pacific hurricane season
*
1997 Atlantic hurricane season
*
1997–98 South-West Indian Ocean cyclone season
*
1997–98 Australian region cyclone season
The 1997–98 Australian region cyclone season was a slightly below average tropical cyclone season. It ran from 1 November 1997 to 30 April 1998. The regional tropical cyclone operational plan also defines a ''tropical cyclone year'' separately f ...
*
1997–98 South Pacific cyclone season
*
1997 North Indian Ocean cyclone season
The 1997 North Indian Ocean cyclone season had no bounds, but cyclones tend to form between April and December, with peaks in May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the north ...
*
1998 Pacific typhoon season
The 1998 Pacific typhoon season was at the time the least active Pacific typhoon season on record, until the record was surpassed 12 years later, spawning 16 tropical storms and 8 typhoons. The scope of this article is limited to the Pacific Oce ...
References
{{DEFAULTSORT:1997-1998 El Nino Event
El Nino 1997-98
El Nino 1997-98
1997-98