BEACH CHANGES CAUSED BY THE ATLANTIC COAST STORM OF 17 DECEMBER 1970 
by 
Allan FE. DeWall, Patricia C. Pritchett, and Cyril J. Galvin, Jr. 
I. INTRODUCTION 
On 17 December 1970 a storm of moderate intensity affected the Atlantic 
coast from North Carolina to New England. This report relates character- 
istics of this coastal storm to the resulting beach changes at selected 
localities. As part of the U.S. Army Coastal Engineering Research Center 
(CERC) Beach Evaluation Program (BEP), 91 beach profile lines at seven 
localities between Cape Cod, Massachusetts, and Cape May, New Jersey 
(Fig. 1), were surveyed from the frontal dune or bulkhead to the low tide 
terrace before and after the storm. The variables analyzed and discussed 
include: (a) Environmental measurements of the storm's intensity, includ- 
ing winds, waves, and tidal heights; (b) beach changes, including the 
change in horizontal position of the mean sea level (MSL) contour, and the 
change in area above MSL between the prestorm and poststorm profiles; and 
(c) correlations between the storm characteristics and resulting beach 
changes. $ 
DeWall, Pritchett, and Galvin (1971) is a condensed version of the 
present report. Additional information on the BEP and the 17 December 
storm is given in Galvin (1968), Pritchett (1971), and DeWall (1972). 
The present report contains revised estimations of some data in the earlier 
reports, and is the source for most of the data in Table 4-5 of U.S. Army, 
Corps of Engineers, Coastal Engineering Research Center (1975). 
II. METEOROLOGY OF STORM 
1. Characteristics and Path of Low-Pressure System. 
The storm began as a low-pressure area over northeastern New Mexico 
on 14 December 1970. By 2200 hours e.s.t. on the 15th, the center of 
the low had crossed Texas and Oklahoma and was on a northeastern path 
across Arkansas (Fig. 2). It continued on this trajectory until reaching 
southern Indiana where it turned eastward, moving toward the coast. Late 
on the evening of the 16th, the center passed over Salisbury, Maryland, 
and began heading northeast, crossing the Delmarva Peninsula and moving 
out over the ocean. At 0400 hours on the 17th, the low was centered just 
off Cape May; the central pressure was about 998 millibars. Six hours 
later the low, centered off New York began to strengthen (deepen). The 
pressure dropped to 992 millibars as is passed Nantucket, Massachusetts. 
As the low began moving east-northeast, the distance between the coast and 
the center increased. On the afternoon of the 18th, the center passed 
over Nova Scotia, and then continued toward Greenland. 
2. Windspeed and Wind Direction. 
Wind vectors for Atlantic City, New Jersey, New York City, Boston, 
Massachusetts, and Portland, Maine, are presented in Figure 3. The 
