Syzygy, Tides and Jonathan White

My arms ached as I pulled back and down on the boom, windsurfing towards an island on one of the last tacks I had the energy to make to avoid the embarrassment of a rescue. I zigzagged shoreward. The wind on my sail brought me closer, but the tide pulled me away. A fall would allow the tide to take me further from my goal: wet, jagged, barnacle-encrusted rocks along the water’s edge. Finally, I reached land, released the boom, made my way with water-shriveled feet through the barnacles, pulled the rig up a safe distance from the sea’s surface, and thanked my lucky stars.

tides-2-14-2017-11-42-24-amIn the introduction to his new book, author Jonathan White, who, like me, “lives on a small island in Washington State,” recounts the perilous event that made him (p 5) vow “to learn more about the tides,” which led him to write Tides, “a travel adventure, personal journey, cultural history, and provocative scientific inquiry into the forces that keep the earth’s waters in constant motion.” It is as great a book for those who are part of the (p 17), “More than half of the world’s population [that] lives on or near the coast,” as for those who aren’t.

deception-pass-state-parkMost of what I know about tides, I learned from Tides4Fishing, including information about: sunrise and set, the moon’s phase, the earth’s current distance from the sun, tidal coefficients and, of course, low and high tide times and heights for any given day for hundreds of locations worldwide. I care most about Cornet Bay, where I like to go crabbing and beach combing. Because it’s off the beaten path from the rest of Deception Pass State Park, or maybe due to the conditions along the beach at very low tide, it’s a great place to go, alone, to encounter sea creatures. Doing so requires a willingness to walk through muddy, sometimes slippery conditions, but this is the place where I’ve seen the seen the biggest variety of sea life with the fewest fellow beach combers, including: sea stars, plumose anemones, crabs, sea pens, burrowing anemones, dog whelks and blue top snails.

I combed through the tide data for Cornet Bay during 2017, which confirmed what I already knew: the lowest tides between sunrise and sunset occur during the summer months. In winter, they take place at night.

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What I learned from White’s book was ten times what I knew from the time I spent at my favorite tide site **Spoiler Alert-the following paragraph contains information that you may not want to know if you plan to read the book, proceed with caution**:

contents-2-14-2017-12-45-14-pmChapter 1 (Pp 34-35), “the moon, although smaller than the sun, is much closer to the earth and exerts about twice the sun’s influence on the tide;” Ch 2 (p 59), “The alignment of earth, moon, and sun is called syzygy. When the moon is full, it’s in opposition, when new, it’s in conjunction;” Ch 3 (p 82), “All rivers with tidal bores have two things in common. The first is a funnel-shaped river mouth with a gently sloping bottom. The second is a large tide at the river’s entrance. When this large tide–in the Qiantang’s case, twenty-six feet–enounters the shallowing river mouth, the energy shifts dramatically…It’s been said that a tidal bore is a sonic boom traveling upriver;” Ch 4 (p 121), “In a month’s time [the moon] darts like a hummingbird from 28 degrees north of the equator to 28 degrees south of the equator and back again…Newton figured that the moon’s migration north and south of the equator (its change in declination) must play a role in the varying heights of the daily tides;” Ch 5 (p 153-154) “an amphidrome has a center hub where…there is little or no tide. The arms or spokes rotate, with the highest tides in each amphidrome occurring farthest from the center hub…these circling arms are indeed waves traveling at 450 miles per hour;” Ch 6 (p 179) “The effect of global tidal friction usually acts as a break on the earth’s rotation, making each day 1/50,000 second longer. And as tidal braking slows the earth’s rotation, energy is transferred by angular momentum to the moon, speeding it up and pushing it away at a rate of about an inch and a half per year, or ten feet in a human lifetime;” Ch 7 (p 209), “Of the four hundred tide-generating constituents, only 12 are responsible for 90% of the tide, 90% of the time…;” Ch 8 (p 245), “Scientists agree that the 3.5 terawatts of global tide energy is the correct theoretical measure of the total, based on the physics.” Ch 9 (p 262), “the most extreme tides happen when the sun and moon are nearest the earth and as closely aligned as theoretically possible.” And that’s just about the tides! The stories of the people and the creatures whose lives intertwine with the tides are even better.

White also includes several pieces of information of local interest: (p 161) a nautical chart gives warning about Deception Pass, “rips and boils…should not be attempted by a small boat during maximum tidal currents;” (p 170), “Today, the Samish tribes believe Ko-Kwal-alwoot and her spirit-lover look after the people’s welfare. The turbulence in the water is Ko-Kwal-alwoot’s long hair, reminding the people of her presence, and (p 249) “In Washington State, Snohomish County PUD… planned to install two eighteen-foot-diameter, 150 kilowatt [tidal energy] machines…they would have been in Admiralty Inlet for five years…After years of research…due to funding shortages, the project was abandoned before the machines were installed.”

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low-tides-2-14-2017-11-39-29-am-bmpTides4Fishing also provides information of local interest for beach combing aficionados: the lowest tides of the year (see table) so save the dates. Besides Cornet Bay, the Urchin Rocks at Rosario Beach and Penn Cove in Coupeville are great places to encounter marine life on North Whidbey/South Fidalgo Island. Save the date, 22 February at 7:00 pm, if you’d like to learn more about Tides from the author himself. Jonathan White discusses the subject at the Anacortes Public Library. It’s free and open to the public. Something to ponder in the meantime, my favorite pre-chapter quote from White’s book (p 44), “The most admirable thing of all is this union of the ocean with the orbit of the Moon. At every rising and every setting…the sea violently covers the coast far and wide…and once this same surge has been drawn back it lays the beaches bare…as though it is unwittingly drawn up by some breathings of the Moon.”

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