What Is La Nina? Is The Natural Phenomenon Worse Than El Nino?
In its monthly report, the CPC, which is part of the National Oceanic Atmospheric Administration, said that El Nino was unlikely to cause extreme weather in the Northern Hemisphere. Some of the CPC's models predict weak La Nina conditions, but most of their forecasts show neutral U.S. conditions this summer, with neither El Nino nor La Nina episodes.
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So what is La Nina, and how does it differ from El Nino?
More people probably know the name El Nino than La Nina, but they're both destructive forces. While they are opposites in how they affect rain, drought and flooding conditions, one isn't really worse than the other.
La Nina, sometimes referred to as the "anti-El Nino," is an ocean-atmosphere phenomenon. When La Nina strikes, the sea-surface temperature across the equatorial Eastern Central Pacific Ocean lowers, but will be lower than normal by about 37 to 41 degrees Fahrenheit. A La Nina can last between nine months to two years.
According to the National Oceanic Atmospheric Administration, the result of a La Nina episode is drier than normal conditions in the Southwest in late summer through winter, with dry conditions in the Central Plains in the fall and in the Southeast in the winter. These conditions can wreak havoc on crops. In 2011, for instance, La Nina caused crippling droughts in Texas. La Nina also resulted in dry spells in South America, where it wiped out crops.
At the same time as La Nina dries out southern parts of the country, it causes wetter conditions than normal in the Pacific Northwest in the fall and winter.
With El Niño, the opposite of La Nina, sea surface temperatures rise, causing increased rainfall in the southern U.S. and destructive flooding along the coasts of places like Peru and Chile. On the flip side, El Nino leads to droughts in Southeast Asia and Australia, where brush fires sometimes are blamed on El Nino. Major food staples from these areas, like sugar cane and grains, can be destroyed by the dry conditions.
To monitor ocean conditions and predict the arrival of an El Nino or La Nina, the NOAA operates a network of buoys. These buoys measure temperature, currents and winds along the equator, transmitting data daily to researchers and forecasters.
The NOAA says that El Nino and La Nina every three to five years on average. Since 1975, La Ninas have been half as frequent as El Ninos.
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