Does El Niño cause tornadoes?
No. Neither does La Niña. Both are major changes in sea surface temperature in the tropical Pacific, which occur over the span of months. U.S. tornadoes happen thousands of miles away on the order of seconds and minutes. El Niño does adjust large-scale weather patterns. But there are too many variables to say conclusively what role El Niño (or La Niña) has in changing tornado risk; and it certainly does not directly cause tornadoes. A few studies have shown some loose associations between El Niño years and regional trends in tornado numbers from year to year; but that still does not prove cause and effect. Weak associations by year may be as close as the El Niño-to-tornado connection can get—because there are so many things on the scales of states, counties, and individual thunderstorms that affect tornado formation.
