HURRICANE TIDAL FLOODING 



B-11. GENERAL 



In the last 18 years the Narragansett Bay area lias been 

 subjected to severe tidal flooding from two major hurricanes - 

 those of September 1938 and August 195U (Carol) - and moderate 

 flooding from the hvirricane of September 19hh' Mnor flooding 

 has also occurred as the result of about 22 other hurricanes 

 and severe storms in the past 50 years. Detailed descriptions 

 of these three hurricanes are given in the following paragraphs. 



B-12. HURRICANE OF SEPTEMBER 21, 1938 



The damage caused by tidal flooding from this hurricane 

 was the highest ever experienced in the Narragansett Bay area. 

 Probably the most significant factor, which produced the record 

 high water, was that the peak of the wind-induced tidal surge 

 arrived at approximately the time of the predicted high tide. 

 At Newport Harbor, where the water attained a height of 10.8 

 feet above mean sea level, the hurricane tide occurred approxi- 

 mately three-quarters of an hour before the normal high tide, 

 but at Providence and Fall River-Somerset, Massachusetts, the 

 two occurred at about the same time and reached elevations of 

 15.7 and 13.7 feet, m.s.l., respectively. Pertinent data 

 concerning tidal heights, wind velocities and barometric pressures 

 are included in Table B-It.. 



The winds accompanying the hurricane of September 1938 were 

 generally in excess of 75 m.p.h. in the Narragansett Bay area. 

 At Block Island, the wind attained a maximum recorded 5-minute 

 sustained velocity of C2 m.p.h. from the southeast and maximum 

 gusts of 91 m.p.h. before the anemometer was blown down. A max- 

 imum 5-minute velocity of 87 m.p.h. from the southwest and gusts 

 of 125 m.p.h. occurred at Providence. Minimum barometric pressures 

 of 28.66 and 2S.90 inches, respectively, were recorded at Block 

 Island and ProAddence. The foivard speed of the hurricane near 

 Narragansett Bay was about $$ knots (63 m.p.h.). Tide curves show- 

 ing the predicted and estimated tidal elevations at Newport, _ 

 Providence and Fall River - Somerset are included as Plate B-1. ■ 

 Hurricane flood levels based on observed high water marks, along ™ 

 the east shore of Narragansett Bay are shown on Plate B-6, and 

 for the Sakonnet River (from Sakonnet Point), Mo\mt Hope Bay and 

 the Taunton River as far as Dighton, Massachusetts, on Plate B-7. 

 The high water profile for the west shore of Narragansett Bay is m 

 similar to the east shore, as indicated by office records. ■ 



B-10 



