Weather, and the effects of climate patterns, are quite fascinating. Certain meteorological conditions that begin in one region aren’t isolated strictly to that area and are so powerful, that they can affect the entire world. A prime example is El Niño, and its counterpart La Niña, climate patterns in the Pacific Ocean that have significant global impacts on weather, economies, ecosystems, and more. This weather pattern wreaked havoc in North America.
Both patterns are part of the El Niño Southern Oscillation (ENSO) cycle. According to the National Weather Service, El Niño refers to the above-average sea-surface temperatures that periodically develop across the east-central equatorial Pacific and La Niña is the periodic cooling of sea-surface temperatures across the east-central equatorial Pacific. El Niño years typically mean dryer conditions in certain areas, which can lead to increased wildfires, and more rain in others, while La Niña years can lead to more severe hurricanes.
Scientists overlooked El Niño events for much of the 20th century as they often appeared weak. That changed in 1982 when profound weather effects caused increased interest in the phenomenon. Since then, several El Niño events have shocked scientists and caused widespread destruction. (Learn about the different times extreme weather changed the course of history.)
To compile a list of El Niño events that shocked scientists, 24/7 Tempo consulted a range of weather and news publications including the Woods Hole Oceanographic Institution, The Week, and the Golden Gate Weather Services. Next, we selected events that had an outsized effect in terms of environmental changes, fatalities, and infrastructure damage. After that, we confirmed aspects of the events using sites like CNN and the Los Angeles Times.
1982–83 El Niño event
While experts were long aware of strange weather cycles, the 1982-83 El Niño event shocked scientists and caused a renewed interest in the climate phenomenon. Signs of El Niño appeared in early 1982 with a noticeable drop in atmospheric pressure along the Pacific Coast of North America. The general public had little knowledge of El Niño at the time and scientists were busy with a volcanic eruption in Mexico, however, so this weather pattern went unnoticed until the season had ended.
Regardless, the signs were evident in the strange weather occurrences in those two years. Eurasia and North America experienced unusually high temperatures, which resulted in the warmest winter in the Eastern US in over 25 years. Indonesia and Australia faced bad droughts. Hawaii experienced one of the worst cyclones in its history. Heavy rainfall in Ecuador increased shrimp harvests but also led to a massive outbreak of malaria. The unusual water temperatures effectively killed off multiple species of fish and algae around the Galápagos islands.
Beyond the environmental effects, the 1982-83 El Niño event transformed the usually intense hurricane season into an otherwise unremarkable period. Early estimates put the total damages at $8 billion, though later studies forecasted the number to be as high as $4.1 trillion. Ultimately, the 1982-83 El Niño event was an existential event, giving shape to a long-occurring but little-understood cycle of anomalous weather patterns.
1997–98 El Niño event
While many similar weather events caused untold destruction, not many compare to the 1997-98 season. Scientists were shocked at this El Niño event, declaring it one of the most severe Southern Oscillations in recorded history. Its power began fomenting in early January of 1997 after scientists measured a noticeable increase in ocean temperatures. These temperatures continued to rise until June of 1997 when El Niño truly began.
Across the Pacific Coast of North America, a path of warm water formed, stretching from Alaska to Mexico. This weather anomaly created so much extra heat, that it produced around 93 times the amount of energy produced by all fossil fuels in 1995. As such, an inordinate amount of cyclones formed. The West Pacific basin saw a record 11 super typhoons form, with all but one reaching Category 5 intensity.
Beyond tropical storms, considerable events occurred due to El Niño. Indonesia faced a record drought. California saw record rainfalls and Florida experienced its worst tornado outbreak in history. Furthermore, the high ocean water temperatures caused an estimated 16% of the world’s reef systems to die.
Remarkably, the heavy rainfall in Kenya caused a severe outbreak of Rift Valley Fever. Ultimately, the 1997-98 El Niño event caused $32–96 billion in damages. (For other intense storms, discover 7 weather records we hope will never be broken.)
1997 Pacific hurricane season
The 1997-98 El Niño shocked scientists, but few realized the profound effect it had on that year’s hurricane season. Starting on May 15, 1997, the hurricane season began, running until weather patterns changed in early December of the same year. An active hurricane season, the 1997 cycle produced 17 named storms and 9 hurricanes, with 7 of them becoming major hurricanes.
Tropical Storm Andres hit first in late June, killing multiple people. Tropical Storm Ignacio followed but caused minimal damage thanks to its unusual flight path. In early September, however, Hurricane Linda hit and became the biggest east Pacific hurricane in history (until Hurricane Patricia broke the record in 2015). At one moment, Linda’s winds reached 185 mph. Hurricane Pauline, however, caused the most damage, killing hundreds of people in Mexico.
Thanks to a notably strong El Niño event, the 1997 Pacific hurricane season caused extensive destruction. Records say between 261 and 531 people were killed, with countless more injured. Ultimately, the season caused around $551 million in damages (1997 currency).
2014–2016 El Niño event
As temperatures mounted in the ocean along the South American coastline, the 2014-2016 El Niño event suggested profound effects on the global environment. Such speculation proved true, and the El Niño event shocked scientists due to its wide-reaching effects. By all estimates, experts consider the 2014-2016 El Niño season to be the strongest on record.
Indeed, nowhere in the world was safe from its effects. South America bore both heavy droughts in the north and excessive rainfall which led to floods and subsequent displacement of people in the south. Less than expected rainfall caused droughts to occur across Southeast Asia. Africa received excessive rainfall, which caused countries like Lesotho, Swaziland, and Zimbabwe to declare national emergencies.
Meanwhile, the United Kingdom received record rainfall, excessive flooding, and strangely high temperatures. While death estimates for this El Niño season remain elusive, the weather activity caused extensive damage. Due to less-than-expected rainfall, Indochina experienced a stark drop in food production. Africa was the worst hit, however.
Over 60 million people met hunger and malnutrition crisis, with 10 million people in Ethiopia alone put at risk. Ultimately, the 2014-16 El Niño event caused both 2015 and 2016 to be two of the hottest years on record.
2015 Pacific hurricane season
The 2015 Pacific hurricane season shocked scientists because of its relationship to El Niño events. Between May and December of 2015, 26 named storms wreaked havoc on the Pacific coast of North America. Due to the unusually strong 2014-2016 El Niño event, scientists consider the 2015 Pacific hurricane season to be the second-strongest Pacific hurricane season on record.
That summer, multiple large hurricanes originated near Mexico and made their way either up the coast or out into the Pacific Ocean. It started with Hurricane Blanca in June, preceding Hurricane Carlos and Hurricane Dolores. By the end of August, three Category 4 hurricanes worked their way through the East Pacific simultaneously for the first time in recorded history.
By season’s end, countless damage occurred across the region. The combined hurricane forces killed a total of 45 people and injured hundreds more. Across the regional basin, the various storms caused $566 million in damages. Hurricane Patricia in October alone, became the most intense hurricane ever recorded in the Western Hemisphere.
2023–2024 El Niño event
Scientists consider the 2023-24 El Niño-Southern Oscillation event the fourth most powerful in recorded history. Starting on July 4, 2023, this event resulted in extensive droughts, widespread flooding, and other shocking natural occurrences. That month, scientists recorded warmer global air surface temperatures than any month of the previous year.
From there, it took another month before strange weather patterns emerged. In August, India recorded its driest month since such parameters were first recorded in 1901. This was unusual as late summer typically marks the beginning of monsoon season in the region. Simultaneously, temperatures in central Brazil reached as high as 41 °C.
However, it took another month for El Niño to sow destruction. The Rio Grande do Sul floods occurred in the Brazilian state of the same name. It killed at least 47 people, injured 940 more, and resulted in $1.3 million in damages. In late November/early December, flash floods and excessive rainfall tore through East Africa, killing 136 people and displacing nearly half a million.
Then in May 2024, Brazil took another hit. The 2024 Rio Grande do Sul floods occurred, killing 181 people, injuring over 800, and resulting in $3.7 billion worth of property damage. (For other strange climate patterns, explore strange weather events you won’t believe.)