Tide
Book: A Must Read for Every Beach Hiker
Our family
members are all enthusiastic beach walkers, so we want to know in advance
when it's the opportune time (low tide) to saunter the shore. We'll walk
the coast just about anytime but have learned (sometimes the hard way)
that it's best to begin a beach hike a few hours before low tide and finish
a few hours after.
Before we hit the beach, I always consult a tide book, one of those trading
card-sized pamphlets that chart the ocean's rise and fall, sunrise, moonrise
and so much more. Where else can you get so much earthly and heavenly
knowledge for free?
Two high tides and two low tides occur every 24 hours and 50 minutes.
(It would be convenient for beach hikers to make it an even 24 hours,
but the tides are governed by the gravitational pull of the moon and sun-over
which we have no control.) Last year's tide book is no more useful than
last year's calendar.
So far this year I've picked up three different tide books-from an REI
store, a maritime museum and Pt. Reyes National Seashore. The tide book
I purchased from REI cost me $1, the one from the private sector was free,
and the one from the National Park Service cost only a quarter.
I appreciate those newspapers that publish daily tide tables, but I really
prefer holding all 365-days worth of tides in my hand in the form of one
of those little tide books. I favor tide books that print out the heights
and times of the tides over those that graph the tides like corporate
profits in an annual report.
Of course, you have to be sure your tide table is up-to-date. Last year's
tide chart is as useless as a Minnesota road map in Massachusetts. And
a Maine tide table won't do you much good in North Carolina. Sometimes
a hundred miles or so doesn't make that much difference. A San Diego beach
hiker could use a Los Angeles tide book and be accurate merely by subtracting
ten minutes from L.A.'s tide times.
Responsibility for predicting tides is vested in The National Ocean Survey,
a branch of the National Oceanic and Atmospheric Administration of the
U.S. Department of Commerce. After the agency calculates the astronomical
influences upon our oceans, it factors in such considerations as the shape
of the shoreline, the depth of the water and seafloor topography.
Americans who live near the Pacific, Atlantic and Gulf coasts live in
rhythm with the tide. About 80% of all Californians reside within an hour's
drive of the coast. And about 100% of Rhode Islanders live within an hour's
drive. High percentages of Washingtonians and Floridians live close to
the ocean.
(By the way, you residents of the heartland are not altogether removed
from tidal forces. To a lesser extent, tides also occur in lakes, the
atmosphere and even within the very crust of the earth, acted upon by
the same gravitational forces of the moon and the sun that so influence
ocean waters.)
Judging from the millions of this handy booklet in print, I'm hardly the
only one who thinks tide books, usually bearing such scintillating titles
as "Tidal Calendar" or "High and Low Tides," are a
great read. My favorite tide books have local lore, wind chill factor
charts, grunion run predictions and favorite recipes for clam chowder.
The humble tide book is unlikely to make the best-seller list (most are
given away free), but is an indispensable, positively cosmic reference
for the beach hiker, seashell collector and tide pool explorer.
Take a beach hike. But read a tide book first. |
