King tides are making a grand entrance this week, potentially causing coastal flooding along several U.S. shorelines. These exceptionally high tides happen when the gravitational forces of the sun and moon align, magnifying the tidal ranges. The impact is most pronounced when the moon is nearest to Earth—a point known as perigee—which coincides with this month’s supermoon. Consequently, coastal regions like Charleston and Miami are expected to see significant water level increases, likely triggering coastal flood alerts by the middle of the week.