Seesaw Pattern (IMAGE) Columbia Climate School Caption When ENSO is in a hot, or El Niño, phase (top), the frequency of tornadoes goes down. When it is in a cold, or La Niña phase, tornadoes increase. The effect is strongest in the boxed area. Credit Allen et al., Nature Geoscience, 2015 Usage Restrictions Credit must be given License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.