The strongest El Niño in more than a decade is the culprit behind the wretched weather bombarding much of the country this winter, from the snowstorms that buried the mid-Atlantic states in December to the rains that drenched California last month. “Ocean temperatures are somewhere upwards of two degrees above average,” a meteorologist tells NPR. “So we have had what we would characterize as a strong El Niño.”
It’s the strongest, in fact, since the winter of 1997-98. El Niño years occur when the warmer surface waters of the Pacific move east, altering the flow of two major jet streams. That tends to pull more storms toward California and the Gulf area, while drying out Indonesia—and parts of Indonesia have been plagued with fires recently. Scientists expect this season's El Niño to stick around for another month or two. (More El Nino stories.)