CHAPTER I 



INTRODUCTION 



1 . Background 



Redfield and Miller (1957) considered the changes in water level 

 associated with hurricanes as consisting of three successive stages; 

 the forerunner surge, the hurricane surge and the resurgence. The 

 forerunner surge is the gradual rise in water level along the coast 

 which precedes the arrival of the hurricane. It occurs while the 

 storm center is at a great distance from the coast, irrespective of 

 whether the storm reaches the point of observation. The gradual 

 buildup of water level may reach one meter. This may seem 

 unimportant in a destructive sense when compared to the hurricane 

 surge itself, but it is an important initial boundary condition for 

 local storm surge models. 



The salient feature of forerunners is that local atmospheric 

 forcing is not required for this phase of the surge. Cline (1920) 

 reported the existence of forerunner surges in the Gulf of Mexico. 

 He analyzed water levels and winds associated with hurricanes from 

 the 1900-1919 period and found that some storms clearly produced 

 increasing sea level within 24 h of the disturbance entering the 

 Gulf. Cline postulated that forerunners are related to swell 

 generated by Gulf hurricanes. Based on a simple wind model, Cline 

 showed that the storm generated swell (forerunner) would be 

 significant only in the direction of the hurricane motion. The data 

 presented by Cline, however, suggest the nearly simultaneous 



