El Niño and La Niña

(without the Mumbo-Jumbo)

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El Niño/La Niña Glossary

NOAA says 2006 was the second warmest on record (avg: 54.90ºF) for the United States.
(A mild December helped raise the yearly average to 0.08ºF below 1998)

The World Meteorological Organization says the 1997-'98 El Niño was the strongest in the 20th Century.  It was a major factor in 1997's record high temperatures.  The estimated average surface temperature for land and sea worldwide was 0.8ºF higher than the 1961-1990 average of 61.7ºF.

According to NOAA, 1998 set new all-time record global land
and ocean surface temperatures, above 1997's record high levels.
1998's anomaly of 1.2ºF above the long-term (since 1880)
mean of 56.9ºF is the 20th consecutive year with an annual
global mean surface temperature higher than the long-term average.

NOAA says the La Niña Winter of 1999-2000, December through February, was the warmest on record (since 1900) for the United States.

El Niño is characterized by a large scale weakening of the trade winds and warming of the surface layers in the Equatorial eastern and central Pacific Ocean.  El Niño events occur irregularly at intervals of 2-7 years, although the average has been, until recently, about once every 3-4 years and lasting 12-18 months. (see Table)

El Niño events often result in flooding in California and parts of the midwestern United States, while the southern half of the US experiences cooler-than-normal winters.  Winters are generally warmer than normal in the northern half of the US.  During El Niño years, there are fewer hurricanes in the Atlantic.

Average El Niño Winters Worldwide
(map courtesy of  NOAA / CPC / NCEP)

Average El Niño Summers Worldwide
(map courtesy of  NOAA / CPC / NCEP)

There has been a confusing range of use for the term "El Niño" by both the scientific community and the general public.  Originally, the term El Niño (the young boy, in reference to the Christ child) denoted a warm southward-flowing ocean current that occurred every year around Christmas off the west coast of Peru and Ecuador.  The term was later restricted to an unusually strong warming that disrupted local fish and bird populations every few years.  However, as a result of the frequent association of South American coastal temperature anomalies with interannual basin-scale equatorial warm events, El Niño has also become synonymous with larger scale, climatically-significant, warm events.

Conversely, La Niña is the cold counterpart of El Niño where sea surface temperatures in the tropical Pacific fall below normal.  This phase is characterized by warm winters in the southeastern United States, colder-than-normal winters from the Pacific Northwest to the Great Lakes, and unsettled winters in the Northeast and Mid-Atlantic states.
The original name given to this Cold Phase was "El Viejo" meaning  the old man.

Average La Niña Winters Worldwide
(map courtesy of  NOAA / CPC / NCEP)

Average La Niña Summers Worldwide
(map courtesy of  NOAA / CPC / NCEP)

El Niño

La Niña

early 2006
late 2010 - early 2011
2015 - mid 2016late 2016

El Niño

La Niña

Until the 1997-'98 El Niño, the 1982-'83 episode had been the strongest and most devastating of the 20th Century.  During that period, the trade winds not only collapsed--they reversed.

It caused weather-related disasters on nearly every continent.  Australia, Africa and Indonesia suffered droughts, dust storms and brush fires.  Peru received the heaviest rainfall on record: 11 feet in areas where 6 inches was normal.

The 1982-'83 El Niño was blamed for as many as 2,000 deaths and more than $13 billion in damage to property and livelihoods worldwide.  During this period, the thermocline off the South American coast dropped to about 500 feet.  On September 22, in just 24 hours, sea-surface temperatures along the coastal village of Paita, Peru rose 7ºF.

1982-'83 U.S. El Niño Damage Statistics (from FEMA)

Continental United States $2 billion Storms and flooding
Gulf States $1.2 billion Floods
Mountain and Pacific States $1 billion Heavy rains
Hawaii $230 million Hurricane strengthened by El Niño

There were also secondary problems caused by the 1982-'83 El Niño.  Encephalitis outbreaks occurred on the east coast of the U.S. attributed to a warm, wet spring fostering mosquitoes.  Snake bites became more numerous in Montana, as the hot, dry weather drove mice from high elevations downward in search of food and water and the rattlesnakes followed.  A rise in bubonic plague in New Mexico resulted from a cool, wet spring providing favorable conditions for flea-carrying rodents.  An increase in shark attacks off the Oregon coast was due to unseasonably warm sea temperatures.

Some meteorologists have tied El Niño to above-normal temperatures in Alaska and northwestern Canada with a reduction in the salmon harvest. (see Canadian Bulletin)

In the eastern United States, the Winter of 1982-'83 was the warmest in 25 years.

(Information courtesy of  NOAA / PMEL / TAO)

What impact will El Niño have on the United States?

Latest Temperature & Precipitation Outlook (NOAA)

© 2015 Dave Granlund

 Latest El Niño/LaNiña Advisory (NOAA / CPC

Sea surface temperature (°C) departure from normal as of 4/4/18

  Southern Oscillation Index (SOI)

  El Niño and Landslides 

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