PART IV: HYDROGRAPHIC DATA 



9. The effects of hurricane Elena upon coastal waters In the Gulf of 

 Mexico were somewhat unusual in that clear evidence of a departure from ex- 

 pected water levels was apparent as early as 28 August when the center of the 

 hurricane was over Cuba (see Plate 5). Abnormally high water levels gulfwlde 

 often accompany hurricanes in the Gulf of Mexico; this effect is traditionally 

 termed the "hurricane induced surge forerunner." However, evidence of a fore- 

 runner usually does not occur until the center of the storm passes through the 

 Yucatan or Florida Straits. 



10. Figures 2 and 3 show the locations of hydrographs contained herein 

 which cover the reach of coastline from Gulf port. Miss., to Carabelle, Fla. 

 The hydrographs were obtained from the area of coastline primarily affected by 

 Elena during the 48 hr prior to landfall and are shown in Plates 1 through 17, 

 Because Elena meandered through the eastern gulf from 29 August until 2 Sep- 

 tember, many of the hydrographs show multiple peaks associated with the storm, 

 particularly along the coast of the Florida panhandle. Table 2 contains a 

 listing of the maximum surge elevations recorded while Elena was in the Gulf 

 of Mexico. 



11. Inspection of the hydrographs may show a higher water level occur- 

 ring on 30 August 1985 than on the day of landfall, 2 September 1985. All the 

 hydrographs with maximum water levels occurring on 30 August are the result of 

 the effects of the storm being superimposed on a high astronomical tide. This 

 is clearly evident in Plate 5 which also shows the predicted tide during this 

 period of time. The maximum surge values contained in Table 2 reflect this 

 fact. Plates 4 and 5 are the hydrographs obtained on the bayward and seaward 

 sides of Dauphin Island, respectively. These hydrographs are particularly 

 noteworthy, as it was this location that experienced the highest winds re- 

 corded on land during the hurricane. 



12. The hydrograph obtained at Gulfport, Miss. (Plate 1), shows a pro- 

 nounced drawdown of nearly 6 ft followed by a rapid increase in water level 

 coinciding with passage of the hurricane. The hydrograph obtained at 

 Pascagoula, Miss. (Plate 3), shows a similar sequence except the drawdown is 

 only about 1.5 ft. In contrast, both hydrographs obtained at Dauphin Island, 

 Ala. (Plates 4 and 5), show a rapid increase in water level of about 4.2 ft 

 followed by drawdowns of about 0.8 ft at the gage on the seaward side of 



