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Table A -2: Enhanced Fuiita Tornado Intensity Scale <br />Category <br />Maximum <br />Equivalent <br />Typical Effects <br />Wind Speeds <br />Saffir- Simpson <br />Scale <br />EF 0 <br />65 - 85 mph. <br />NA <br />Light damage: Causes some damage to <br />siding and shingles. (Hurricane wind speed <br />begins at 73m h. <br />EF 1 <br />86 -110 mph. <br />Cat 1/2/3 <br />Moderate damage: Considerable roof <br />damage. Winds can uproot trees and overturn <br />single- wide mobile homes. Flagpoles bend. <br />EF 2 <br />111 - 135 mph. <br />Cat 3/4/5 <br />Considerable damage: Most single -wide <br />mobile homes destroyed. Permanent homes <br />can shift off foundation. Flagpoles collapse. <br />Softwood trees debarked <br />EF 3 <br />136 - 165 mph <br />Cat 5 <br />Severe damage: Hardwood trees debarked. <br />All but small portions of houses destroyed <br />EF 4 <br />166 - 200 mph <br />Cat 5 <br />Devastating damage: Complete destruction <br />of well -built residences, large sections of <br />school buildings. <br />EF 5 <br />Greater than <br />NA <br />Incredible damage. Significant structural <br />200 mph <br />deformation of mid- and high-rise buildings. <br />4. Thunderstorms. <br />(a) Characteristics of Thunderstorms. Warm, humid conditions encourage <br />thunderstorms as the warm, wet air updrafts into the storm. As warm, moisture rich <br />air rises, it forms cumulus- nimbus clouds, thunderstorm clouds, usually with a <br />flattened top or an anvil shape, reaching to 40,000 feet or more. If this air is unstable, <br />the conditions are then there to cause hail, damaging winds and tornadoes. As a <br />thunderstorm grows, electrical charges build up within the clouds. Oppositely charged <br />particles exist at the ground level. The particles from both top and bottom then race <br />towards each other to complete a circuit. Charge from the ground then surges upward <br />at nearly one third the speed of light to produce lightning. <br />(b) Intensity of Storms. The typical thunderstorm is 15 miles in diameter and lasts an <br />average of 20 to 30 minutes. Any storm is potentially dangerous, especially if affects <br />one locations for an extended period of time. The National Weather Service rates a <br />thunderstorm as "severe" if it produces winds measured at 58 MPH or higher <br />velocity; hail diameters of .75 inch or greater; or the storm or creates a tornado. <br />Lightning is an additional threat during a thunderstorm and its intensity and location <br />is largely unpredictable. <br />(c) Severe thunderstorms most frequently occur in the summer in Cabarrus County. <br />These usually occur in the late afternoon or during the evening or night hours. <br />Summer thunderstorms involve lightning, strong winds and heavy rains that can result <br />localized wind damage, flash flooding and wildfires. The overall impact of <br />Annex A Hazard Identification and Analysis A -4 1 December 20 Achment number 5 <br />F -6 Page 108 <br />