HURRIGAl® CHARACTERISTICS 



27, GENERAL DESCRIPTION 



The term "hurricane" is applied to an intense cyclonic storm 

 originating in tropical or subtropical latitudes (between 5° and 

 20°) in the Atlantic Ocean north of the Equator. Accumulation of 

 heat close to the surface of the water provides energy for water 

 vaporization and the movement of masses of moist tropical air, A 

 hurricane is characterized by low barometric pressures, high winds 

 (75 miles per hour or greater), heavy clouds, torrential rain, 

 tremendous waves and tidal surges, 



28, ORIGINS AJro TRACKS 



Most hurricanes that have affected the eastern coast of the 

 United States have formed either near the Cape Verde Islands or 

 in the western Caribbean Sea, Hurricanes originating near the 

 Cape Verde Islands move westv/ard for a number of days with a 

 fon^rard speed of about 10 miles an hour, then usvially turn north, 

 frequently crossing the West Indies and sometimes striking the 

 eastern coast of the United States, Hxirricanes originating in 

 the Caribbean generally move northward, striking Cuba, the G\ilf 

 "Coast or the. eastern coast of the United States, After re- 

 curvature, the forward speed usually increases to 25 to 30 miles 

 an hour, occasionally to 60 miles an hour. Cape Verde hurricanes 

 commonly recurve (turn northward then east of north) any time 

 after reaching the mid -Atlantic, Hurricanes that affect New 

 England most severely usually arrive from the south-southwest 

 after recurvature east of Florida and after skirting the Middle 

 Atlantic coast, 



29, MINDS AND EARaETRIC PRESSURE 



The highest winds of a hurricane are those within a circular 

 region extending from the edge of the "eye", or calm center, out- 

 ward for 10 to 15 miles. The diameter of the eye is usually about 

 15 miles, although the eye of a matvire hurricane is frequently 20 

 to 30 miles in diameter. Wind movement is not directly toward the 

 low pressure cyclone center or eye of the hurricane but approaches 

 the center in a counter-clockwise spiral. Consequently, the high- 

 est wind velocities occur at points to the right of the center of 

 the hurricane vxhere the spiral wind movement and the movement due 

 to fon/ard motion of tlie center are in the same direction. Since 

 destruction by the v;ind is greatest in the r.rca on the right side 

 of the hurricann, t'-iis area is Icnown as the "dangerous semicircle", 



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