Searching For El Nino

On the other side of the Pacific, where a pool of warm water half again as big as the continental United States has settled, northern Chile has had a foot of rain this year. It is normally one of the world's driest deserts. Santiago had more rain in June and July than it normally gets in an entire year. In Peru, snowstorms have blanketed the Andes, floods have washed through mountain towns and something close to hysteria is gripping the country.

But peripatetic oceanic hot spots do more than affect rainfall nearby. They also drive the world's atmospheric circulation. So when the location of the warm pool changes, so does the weather in regions far removed from the tropical Pacific. "El Nino affects [other parts of the world]," says UC's Hoerling. "But it needs a broker to do it. That broker is atmospheric circulation." As winter approaches, the jet stream that blows across the Pacific from just off the China coast intensifies. El Nino shifts it north. One branch passes over northern British Columbia and never strays into the United States. As a result, fewer storms reach the American Northwest, northern plains, Ohio Valley, mid-Atlantic states and Northeast. All of these regions are expected to have a warmer-than-normal winter with below-average snowfall. The Great Lakes states could even bask in temps 5 degrees above the winter average. But the southern Rockies, especially the eastern face, may experience a dry winter with normal temperatures and a cool spring with high snowfall. Those who fancy spring skiing would do well to book Easter vacations in the Four Comers area.

The other branch of the jet stream is where things get really interesting. In an El Nino year, this "pineapple express" (so named because it starts near Hawaii) shoots across southern California and blasts through to Arizona, the .gulf states and out to the Carolinas. Winter in all of these places is expected to be wetter and colder than normal. Already the sloshing of warm Pacific water from near Indonesia to points east has shifted where tropical storms form. Rather than taking shape in the western Pacific, they are originating farther east, closer to California. In addition, the pineapple express funnels nascent storms toward the West Coast. California could get hit with 50 percent more tropical storms than usual. "Nora may be the first shot down this El Nino storm track," says meteorologist Dan Cayan of Scripps. Although the fact that Nora formed was probably not due to El Nino, where it hit land may be. Scripps's Graham calculates that California could get 50 to 100 percent more rain than normal this winter.

That's what the state is bracing for. In L.A. County, fire stations have stockpiled a million sandbags and are holding tryouts for the elite, 48-member Swift Water Rescue Team. Other counties are holding emergency drills and clearing storm drains of debris, the better to move floodwaters to the ocean as quickly as possible. Cities are drawing up evacuation plans. Will it be enough? The project to build four- to eight-foot walls atop levees along portions of the L.A. River is only 30 percent complete. Some 14 cities and 500,000 people in the southeastern part of the county could face floods four to 10 feet deep. Malibu, the capital of natural disasters, is bracing for the mud and water that will cascade down the hills.

Next month the Federal Emergency Management Agency will convene an El Nino summit to discuss its possible impact throughout the United States. Such a discussion is unprecedented, made possible only because this is the first major El Nino predicted so far in advance. The National Oceanic and Atmospheric Administration issued its forecast last May, thanks to better data and better science: 70 buoys spread across almost one third of the globe in the tropical Pacific measure sea temperature and winds, and computer models of climate turn these readings into climatological predictions. With the 1982-85 El Nino, says Michael McFadden of NOAA, who is on his way to the eastern Pacific to make a service call to the buoys, "we didn't even notice it until it was at its peak. That's not an acceptable way to do business." Now everyone has noticed El Nino. Some of the sightings are certainly mirages. But unlike Elvis, El Nino itself is definitely here.

THE WINDS OF CHANGE: HOW EL NINO WORKS