PERSISTENCE 151 



the Atlantic. And every sailor has heard of the surf around southern 

 Staten Island and Cape Horn. 



Surf, however, is never a wholly regular phenomenon anywhere. 

 Even the Trade Winds do not blow with perfect regularity, but are 

 stronger, on the whole, by day than by night, and at one season of the 

 year than at another. They are also punctuated from time to time 

 with gales of greater or lesser severity on the one hand, and by light 

 breezes, on the other, while they are deformed wherever they blow 

 over or around land masses of any size. They may also be interrupted 

 more or less, near the coast, by the development of a land breeze at 

 night. And the surf caused by the Trades varies correspondingly, 

 though it may never cease wholly on the exposed shore of a coral atoll 

 during the Trade Wind season. 



Regions where the breakers on the coast are the products of passing 

 storms, rather than of prevailingly onshore winds, or where they are 

 caused by swells that radiate out from storms passing at a distance, 

 illustrate the opposite extreme. Under these conditions the surf may 

 vary very widely in violence from place to place, from day to day, and 

 even from hour to hour. The beaches of the middle Atlantic coast of 

 the United States, where the prevailing winds are offshore, or along 

 the shore, and where sea breezes are usually light, afford an excellent 

 example, for it is only during onshore storms that a high surf develops 

 there, or during the rather rare occasions when a heavy swell is heaving 

 in. This may be illustrated by the rarity of breakers higher than 10 

 feet (or even higher than 5 feet) that are recorded at Coast Guard 

 stations, on the beaches of Long Island, New York, New Jersey, and 

 the northern part of North Carolina (table 34). In fact, it is possible 

 to launch a boat from the beaches of our middle Atlantic States and 

 bring it in again on three days, perhaps out of four during the sum- 

 mer, and on one day out of three or four even in the winter, some- 

 thing that would not be possible at all, on any exposed coast in the 

 downwind parts of the Trade Wild Belts, during the windy season. 



Table 34. — Number of days when the average heights of the highest breakers were 

 greater than 5 feet and greater than 10 feet from January through April 1945, at 

 different localities along the east coast of the United States 



[From data obtained through the cooperation of the U. S. Coast Guard with the Woods Hole Oceanographic 



Institution] 



