HURRICANES GENTRY AND SIMPSON 325 



population of 4,000. At Galveston, Tex., in 1900, the center of the 

 hurricane crossed the coastline southwest of Galveston. According to 

 Dr. I. M. Cline [2], the weather observer, "the water rose at a steady 

 rate from 3 p. m. until about 7 : 30 p. m. when there was a sudden rise 

 of about 4 feet in about as many seconds. I was standing at my front 

 door, which was partly open, watching the water which was flowing 

 with great rapidity from east to west. The water at this time was 

 about 8 inches deep in my residence and a sudden rise of 4 feet brought 

 the water above my waist before I could change my position." Ap- 

 proximately 6,000 persons lost their lives in this inundation of Gal- 

 veston. Examples of storms which have done great damage from the 

 storm surge in recent years are hurricane Carol of 1954, the New Eng- 

 land hurricane of 1938, and the Florida Keys hurricane of 1935. 



The high seas associated with the approach to the coast by a hurri- 

 cane are caused largely by the depressed air pressure, the wind force, 

 and certain amplification factors. The air pressure in the center of a 

 hurricane is frequently as much as 2 inches of mercury below normal. 

 The decreased weight on the ocean surface will allow the ocean surface 

 to rise approximately 1 foot per inch of mercury deficiency in air 

 pressure. As the hurricane-force winds move across the surface of 

 the water they induce currents in the ocean that can result in the 

 accumulation of excess water when the hurricane approaches the 

 coast. Neither the deficiency of air pressure nor the piling-up of water 

 along the coast by the wind-driven currents will account for the ex- 

 tremely high tides sometimes observed with hurricanes. There are 

 several theories to account for and explain the amplification of the 

 storm surge while the hurricane is crossing the continental shelf, but 

 they are relatively untested and the final answer may yet have to be 

 determined by researchers. There has been great improvement in the 

 forecasting of storm surges in the last two years and the work now 

 being done by several groups gives promise of great progress in the 

 next few years. 



RESEARCH NEEDS 



At the present time we need more information on almost all facets 

 of hurricanes and tropical cyclones. We need good physical explana- 

 tions of how hurricanes develop, how they move, why they intensify or 

 weaken, and we need to know more about the structure of hurricanes. 

 In recent years, aircraft reconnaissance of hurricanes has greatly in- 

 creased our knowledge of the structure of the storm. Even yet, how- 

 ever, we need much more knowledge of the detailed structure, the 

 areas of inflow and outflow in the hurricane, the structure of the 

 eye, and the mechanisms by which it is maintained. 



Great progress has been made in developing methods for forecast- 

 ing hurricane movement. Most of these forecast methods have been 



