Image caption
(left) Average monthly tornado numbers in the spring (February-April) during El Niño years (red) are less than during neutral years (gray) or La Niña years (blue). (right) During El Niño springs (red), the fraction of days during spring on which the atmosphere adopts a negative-PNA negative pattern is lower than during neutral years (gray). During La Niña years (blue), the fraction of negative-PNA days is nearly twice as high as during El Niño years. Image by Kelsey Malloy.