Query: The temporary drop in sea level in 2010 was due to intense land flooding caused by a strong La Nina.

Relevant passages:
El Niño–Southern Oscillation <=SEP=> El Niño -- Southern Oscillation ( ENSO ) is an irregularly periodical variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean , affecting much of the tropics and subtropics . The warming phase is known as El Niño and the cooling phase as La Niña . Southern Oscillation is the accompanying atmospheric component , coupled with the sea temperature change : El Niño is accompanied with high , and La Niña with low air surface pressure in the tropical western Pacific . The two periods last several months each ( typically occur every few years ) and their effects vary in intensity .   The two phases relate to the Walker circulation , discovered by Gilbert Walker during the early twentieth century . The Walker circulation is caused by the pressure gradient force that results from a high pressure system over the eastern Pacific Ocean , and a low pressure system over Indonesia . When the Walker circulation weakens or reverses , an El Niño results , causing the ocean surface to be warmer than average , as upwelling of cold water occurs less or not at all . An especially strong Walker circulation causes a La Niña , resulting in cooler ocean temperatures due to increased upwelling .   Mechanisms that cause the oscillation remain under study . The extremes of this climate pattern 's oscillations cause extreme weather ( such as floods and droughts ) in many regions of the world . Developing countries dependent upon agriculture and fishing , particularly those bordering the Pacific Ocean , are the most affected .

El Niño <=SEP=> El Niño -LSB- ɛl_ˈniːnjoʊ -RSB- ( -LSB- el ˈniɲo -RSB- ) is the warm phase of the El Niño Southern Oscillation ( commonly called ENSO ) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific ( between approximately the International Date Line and 120 ° W ) , including off the Pacific coast of South America . El Niño Southern Oscillation refers to the cycle of warm and cold temperatures , as measured by sea surface temperature , SST , of the tropical central and eastern Pacific Ocean . El Niño is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific . The cool phase of ENSO is called `` La Niña '' with SST in the eastern Pacific below average and air pressures high in the eastern and low in western Pacific . The ENSO cycle , both El Niño and La Niña , cause global changes of both temperatures and rainfall .   Developing countries that are dependent upon agriculture and fishing , particularly those bordering the Pacific Ocean , are usually most affected . In American Spanish , the capitalized term `` El Niño '' refers to `` the little boy '' , so named because the pool of warm water in the Pacific near South America is often at its warmest around Christmas . The original name , `` El Niño de Navidad '' , traces its origin centuries back to Peruvian fisherman , who named the weather phenomenon in reference to the newborn Christ . `` La Niña '' , chosen as the ` opposite ' of El Niño , literally translates to `` the little girl '' .

La Niña <=SEP=> La Niña ( -LSB- lɑːˈniːnjə -RSB- , -LSB- la ˈniɲa -RSB- ) is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño -- Southern Oscillation climate pattern . The name La Niña originates from Spanish , meaning `` the little girl '' , analogous to El Niño meaning `` the little boy '' . It has also in the past been called anti-El Niño , and El Viejo ( meaning `` the old man '' ) . During a period of La Niña , the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3 to 5 ° C . In the United States , an appearance of La Niña persists for at least five months . It has extensive effects on the weather in North America , even affecting the Atlantic Hurricane Season .