King Tides

If you want an idea of what coastal life will be like in 2080, after seventy more years of global warming and the melting of the polar ice caps, then go down to the beach today and tomorrow around noon (in Cotuit) when the tide is high and exhibiting the rare, but annual phenomenon known in the southern hemisphere as a “King Tide.”

King tides are high tides that occur when the moon, sun, and earth line up in a straight shot called “perigee” and “perihelion.” The earth experiences two such King tides per year, always during either perigee or perihelion and during a forthnightly spring tide which occurs on a full or a new moon.

The moon is new now, and we should see high tides at levels, according to the scientists, that will be in line with forecasts for overall, normal high tides in 2080. The New York Times today quotes Kate Boicourt, an ecologist with the New York-New Jersey Harbor Estuary Program: ““What we’re seeing Wednesday and Thursday is probably what we normally will be seeing by 2080.”

I have personally noticed, and others have commented, that the Cotuit shoreline can get especially innudated on a spring tide, making beach walks impossible along popular stretches of sand such as Ropes Beach and Codman’s Point. In fact, on a moon or spring tide I have to remember not to take the dog on a stroll during my lunch hour as high tide in Cotuit during a full or new moon always coincides with noon and midnight.

Low tides are also extreme during King Tides, so expect to see some extraordinary exposure of sandbars and mud banks — making shoreside clamming a little more interesting as hither before depths become accessible making the older chowder-sized quahogs vulnerable to raking.

Tidal science is interesting stuff — I got a taste of it in the mid-1990s when a partner and I tried to get a tide table capability on our saltwater fly fishing site, Reel-Time. We gave up, but there is a good example of such a site at


Author: David Churbuck

Cape Codder with an itch to write

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