El Niño events, particularly strong ones like a 'super El Niño,' can significantly impact sea levels. During these events, weakened winds allow warm ocean water to shift eastward across the Pacific, creating Kelvin waves. These waves, though invisible on the surface, raise sea levels by 6-12 inches as they travel along the coast. Additionally, Kelvin waves bring warmer water, which can intensify marine heatwaves and further contribute to thermal expansion, compounding the effects of sea level rise.