El Niño and La Niña

Aug 27, 2009

Q:  With hurricane season here, you hear a lot about El Niño and La Niña. What’s the difference?

A: The main difference between the two involves water temperature, explains John Nielsen-Gammon, a weather expert at Texas A&M University. El Niño and La Niña – Spanish for “the child” – both occur in the central Pacific Ocean. “During an El Niño event, which can last almost a year, the waters in that region are warmer than usual,” he says. “The opposite occurs during a La Niña – the waters tend to be cooler than usual. But the important thing is that both events can affect weather patterns in the United States and around the world.”


Q: How do they change our weather?


A:  In years when a La Niña occurs, there are often warmer and drier conditions in many areas, including Texas, Nielsen-Gammon says. “In general terms, a La Niña period means drier weather patterns for Texas. There have been numerous studies on how El Niño and La Niña affect weather patterns, and specifically, hurricanes and their intensity. Some research indicates that the sorts of hurricanes that affect Texas are more common during La Niña periods than during a neutral or El Niño year.”