A better than 50 percent chance exists that the El Niño condition will return this year, and some forecasters fear the weather phenomenon might be among the strongest on record.
The result is a mixed bag for Costa Rica. El Niño is associated with fewer Atlantic hurricanes and perhaps an increase in Pacific storms.
The weather usually is wetter on the Caribbean coast and in the northern zone while drought is likely in Guanacaste, the Pacific coast and the Central Valley.
The strongest El Niño on record was from 1997 to 1998. In the Atlantic there were a below-average seven named storms that year, and only three that rose to the status of hurricane. But the strongest storm was the notorious Hurricane Mitch that killed more than 19,000 persons and did $6.2 billion.
Costa Rica was lucky with just seven dead and damages estimated at about $92 million, much of it in infrastructure and agriculture.
The U.N. Office of Disaster Risk Reduction noted that forecast details were lacking. Ranchers in Guanacaste were urged to move cattle because of the correctly anticipated drought, but they moved the animals into an area that also ended up being hit by lack of rain.
This created an intensified crises, the agency said.
Honduras was devastated by Hurricane Mitch. In Costa Rica the storm’s long-distance effect generated flash flooding and landslides in the northeast. Some 126 bridges and 1,300 kilometers of roadway were affected. The Instituto Meteorológico Nacional in Costa Rica notes that Hurricane Mitch also had a damaging effect on the south Pacific area.
Although El Niño is best known for affecting fishing off the coast of Perú, the impact covers the entire globe.
El Niño occurs every few years, when tropical waters off the Pacific coast of South America turn warmer than normal. Warm air rises off those waters and changes the path of the major wind currents that blow around the planet.
It can weaken monsoons in South and Southeast Asia. Rainy seasons in southern Africa can turn dry. Meanwhile, east Africa and South America can get soaked.
The latest official forecasts give about two-thirds odds that El Niño will develop by the end of the year. But what has really attracted attention is the huge body of warm water building up below the surface of the tropical Pacific.
Meteorologists say there is more energy stored up underwater now than at this point in 1997, just before the strongest El Niño on record developed.
The 1997-98 El Niño led to catastrophic floods in Peru, forest fires in Indonesia and Malaysia and record-high global temperatures. If those warm waters in the eastern Pacific make their way to the surface and stay there, it could mean a major El Niño event, weather havoc worldwide and possibly new high-temperature records.
However, Tony Barnston notes, “Just having a lot of warm water below the surface now is not enough to guarantee that we’re going to have a strong El Niño.” He is chief forecaster at the International Research Institute for Climate and Society.
The warm water could dissipate. It could come to the surface but not linger. Barnston said El Niño is notoriously difficult to predict at this time of year.
Plus, the atmosphere has been in a cooler cycle for the past several years, which many say does not favor a strong El Niño.
Forecasters should have a better picture of what El Niño has in store by August.
What the more distant future holds in a changing climate is even less clear.
“El Niño goes back hundreds of thousands of years, so clearly, El Niño is not related to climate change,” said Mike Halpert, head of the Climate Prediction Center at the National Oceanic and Atmospheric Administration. “Now, the question is, does climate change have an impact? And that’s still an open question.”
The Climate Center issued an El Niño alert Thursday. While a neutral condition is favored for the Northern Hemisphere spring, the chances of El Niño increasing during the remainder of the year exceeds 50 percent by summer, it said.