La nina is an extreme weather phenomenon usually characterized by cooling of ocean temperature and surface waters in the Pacific eventually leading to heavier rainfalls and floods. La nina, which literally means "the girl" in Spanish, is sometimes referred as "anti el-nino."
Basically, La nina together with its predecessor, the El nino phenomenon form the El Niño-Southern Oscillation, an intense climate pattern that occurs in the Pacific ocean. ENSO is best associated with super typhoons and droughts, with the latter brought by El nino and the former brought by La nina phenomenon.
La nina usually follows after El nino in a quasi-periodic ENSO cycle that takes three to seven years. Hence, La nina is the counterpart and exact opposite of El nino. Thus, the La nina phenomenon affects tropical countries in a way of developing strong typhoons and huge floods. On the contrary, European countries and other countries belonging to the western hemisphere are affected by the La nina phenomenon through colder winters and stronger snow storms.
How La nina develops?
According to weather experts and researchers, during the El nino phenomenon, surface water pressures are pretty much lower over the warm waters of the equatorial western Pacific ocean as the hot moist air rises and then completely diverges in an instant. Thus, in the eastern part of the Pacific ocean, surface water pressures become the opposite and is much higher than its western counterpart.
More so, the converging of these two completely different temperatures result in a trading of winds and an eventual rise of waters in the South American region. During the phase of La nina, the rising of the coastal waters are enhanced tenfold, contributing to a much colder water surface temperature.
Effects of the La nina Phenomenon
La nina has a greater effect on tropical countries such as those in the Southeast Asian regions primarily the Philippines, Indonesia, Malaysia and Brunei. Being at the receiving ends of typhoons, those countries experience wetter than normal temperatures resulting into huge floods.
Similarly, the La nina phenomenon also makes the jet stream weaker, strengthening storms and typhoons and enhancing the rain production process. La nina can be potentially catastrophic to a country's economy as it may flood farmland and disrupt the agricultural and food-producing operations.
In the United States, on the other hand, La nina results into a below normal precipitation in the southwest and central parts of America.