As the peak of El Niño draws closer, scientists are growing increasingly concerned about its potential impacts. The impacts of El Niño vary by region, but the West Coast of the U.S. typically sees a significant jump in sea levels. When the temperature of water rises, so does its volume, so El Niño literally causes the Pacific Ocean to expand. By Christmas time, these factors will likely drive sea levels to record-breaking heights and produce high waves and king tides. While the full force of this El Niño remains to be seen, forecasts are increasingly pointing to the strongest event on record.