Little sister, big trouble - La Nina expected to be as troublesome as El Nino - Brief Article

Science World, Oct 19, 1998 by Rachel Rivera

Remember El Nino? After playing havoc with global weather this past year, El Nino is about to be upstaged--by none other than his twin sister, La Nina.

Spanish for "the little girl," La Nina is the flip side of El Nino. Her brother results when weaker-than-normal winds warm up surface waters in the Pacific Ocean (see SW 11/17/97). La Nina exhibits colder-than-normal surface waters, caused by strong winds that stir up cooler waters from the deep and drive them up to the surface.

Depending on wind strength, the Pacific Ocean generally falls under the spell of either El Nino, its warm phase, or La Nina, its cold phase, each lasting an average 12 to 15 months and years. But periods exist when neither one is present, when average winds blow and normal Pacific surface temperatures prevail.

"Right now we're seeing a very vigorous cycle," says meteorologist (weather scientist) Vernon Kousky of the National Weather Service in Camp Springs, Maryland. "From a very strong El Nino, we're seeing a rapid transition to La Nina."

But although her cooler waters have begun to chill El Nino's fever, La Nina is likely to instigate her own set of problems. Meteorologists predict a colder winter in Canada and the northern U.S., more rain in the Pacific Northwest, and a warmer winter in the South. La Nina also tends to spawn an increase in hurricanes.

So brace yourself against yet another weather hooligan. La Nina may prove herself an equal match for her bad-boy brother!