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Hurricanes. Definition. Severe tropical storm in the western hemisphere with sustained winds greater than 74 mph. Formation. Form over water Fueled when energy absorbed during the evaporation of large quantities of water is released during condensation. Characteristics. Shape Movement Eye
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Definition • Severe tropical storm in the western hemisphere with sustained winds greater than 74 mph
Formation • Form over water • Fueled when energy absorbed during the evaporation of large quantities of water is released during condensation
Characteristics • Shape • Movement • Eye • Winds • Storm Surge • Rainfall
Shape • Circular
Movement • 2 motions- own internal spinning and movement across earth’s surface • From east to west, eventually turning northward • Steered by wind currents aloft (weak winds will give it an erratic course)
Eye • Circular- typically around 15 miles wide • Relatively calm and cloud-free, usually rain free • Surrounded by wall cloud where winds and rain are most intense; then inward, spiraling bands of rain clouds
Winds • Spiral counterclockwise inward toward low pressure center (eye) • Not symmetrical about the eye • Strongest to the right of the advancing storm’s eye (approach 200mph) • Strength decreases in relation to distance from the eye
Storm Surge • Rise of water above sea level • Height above sea level is determined by several factors including depth of water along the shore, coastal configuration, and astronomical tide • May reach height of 10’ to 15’ or more (storm surge for Camille, 1969, was 25 feet • Highest to right of advancing hurricane eye • Causes 90% of hurricane deaths
Rainfall • Forms in cumulonimbus clouds • Variable • Clouds spin around center as center moves forward • Most rain falls in area of maximum winds
Destruction • Strong winds – destroy structures • Storm surge • Heavy rains- flooding • Tornados • Residual problems: displacement of snakes, disruption of communications, destruction of utilities, health hazard
Hurricane Season • From June 1 to November 30 for the Atlantic Ocean Basin (Texas season- June to October)
Hurricane Watch • Issued for coastal area when there is a threat of hurricane conditions within 24 to 36 hours
Hurricane Warning • Issued when hurricane conditions are expected in a specific area in 24 hours or less