When you're on the edge of the ocean, high tide comes twice a day. But that daily pattern is not the whole story: There's also a monthly and a yearly pattern to the rise and fall of the tide, caused by the earth's orbit around the sun and the moon's orbit around the earth. The result: "king tides" — a colloquial term, which Wikipedia explains here (see: "King tide"). "The king tides occur when the Earth, Moon and Sun are aligned at perigee and perihelion, resulting in the largest tidal range seen over the course of a year. So, tides are enhanced when the Earth is closest to the Sun around January 2 of each year. They are reduced when it is furthest from the Sun, around July 2."
Winter isn't here yet, but king tides are already happening on the Atlantic Coast. Last week, the Sun and Moon's combined pull had seawater sloshing over streets and sidewalks up and down the Atlantic coastline. The Miami Herald covered the story on October 17 (see: "When the ocean rolls onto the roads, king tide sends a message," by Jenny Staletovich). "Across South Florida over the weekend and early Monday, the seasonal king tide pushed the ocean to places where it didn’t belong," the paper reported. "On Twitter and Instagram, picture after picture showed drivers fording roads and water lapping at sidewalks in a state where more people, and more property, are expected to be at risk from sea rise than any other in the nation."By the end of the century, climate scientists say the seas could rise another three to four feet."
Preventive measures are helping, the paper noted: "In Miami Beach, where tidal flooding has soared 400 percent since 2006, the city is in the midst of a sea rise protection plan expected to cost about $500 million. Considered a leader in resiliency efforts, four new pumps once again helped keep parts of the city dry. 'Areas that two years ago were completely immersed and would require a kayak to cross the street were extremely dry,' said Mayor Philip Levine. They included Indian Creek Drive, Alton Road, North Bay Road and parts of Sunset Harbor, he said."
Far to the north in Boston, Massachusetts, the king tide was also felt, the Boston Globe reported (see: "King Tides have taken over parts of downtown Boston," by Olivia Quintana). And in Boston, as in Miami, the high water played into narratives about sea level rise and coastal development. "Northward along the harbor, the higher tides provided a more serious backdrop. A neighborhood group rallied against plans to erect a new hotel on Lewis Wharf, amid warnings that climate change is raising sea levels," the paper reported. "By early Monday afternoon, water was covering the pilings behind Lewis Wharf, where a developer wants to build a 277-room hotel on the little-used end of the wharf. The group Save Our North End Waterfront says the hotel would ruin access to the pier for residents."
"The state Department of Environmental Protection has ruled that developers could not build the proposed hotel on wharves, piers, or pilings that are submerged in water at high tide," the paper reported. "The move means the developer will likely have to revise the project."
New Hampshire and Maine coastal communities also got wet feet, reported New Hampshire TV station WMUR (see: "King tide points to coastal vulnerabilities to come, experts say," by Jennifer Crompton). It's not an emergency, locals say — "But experts said that with sea rise inevitable, a 1- to 2-foot rise similar to Monday’s king tide will be the norm every day by 2050," the station reported. "'This is really providing a view of what the future is going to look like 20 to 30 to 40 years from now,' University of New Hampshire climate professor Cameron Wake said. The vulnerability might not be as apparent now, but experts said it could get much worse. 'If you combine that with a storm surge or with other types of activity, even just high winds, the level of flooding increases dramatically,' said Jay Diener of the Hampton Conservation Commission."