Indications are growing that an El Niño weather pattern may be forming in the Pacific Ocean, which could have a profound impact on global weather. El Niño events are spawned by unusually warm ocean waters in the Pacific, and these NASA satellite images are one indication of warmer waters.
The images depict sea-surface height anomalies, with above average sea-surface height shown in various shades of brown. Above average sea-surface heights are an indication of warmer waters, which expand as temperatures rise. These two images compare conditions in 1997 — a year with one of the most powerful El Niño events of the 20th century — with conditions this May.
If an El Niño pattern does develop this year, it could lead to wetter conditions in western North America and South America, which could help end a severe drought now plaguing the U.S. West. The 1997/98 El Niño also created warmer and drier conditions in much of Asia. Other evidence, including data from a network of buoys in the Pacific, also shows a deep pool of warm waters sliding east across the Pacific since January.