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Tornadoes take many shapes and sizes, from thin and whispy to thick and massive. It may be helpful to think of tornadoes in three categories: weak, strong, and violent.
Weak Tornadoes:
- 69% of all tornadoes
- Less than 5% of all tornado deaths
- Lifetime 1-10+ minutes
- Winds less than 110 mph
Strong Tornadoes:
- 29% of all tornadoes
- Nearly 30% of all tornado deaths
- May last 20 minutes or longer
- Winds 110-205 mph
Violent Tornadoes:
- Only 2% of all tornadoes
- 70% of all tornado deaths
- Lifetime can exceed 1 hour
- Winds greater than 205 mph
There is another more accurate method of grouping tornadoes according to their strength. this method is known as the "F-scale" and is named after Dr. Ted Fujita who created it. It is used by meteorologists and storm chasers and is sometimes mentioned by television and radio weather reporters.
The "F-scale"
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F#
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Wind Speed
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Damage Severity
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Description
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F0
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40-72 mph
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LIGHT
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Some branches off trees, damaged signs, some windows broken.
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F1
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73-112 mph
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MODERATE
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Peels surfaces off roofs, some trailers overturned, some trees snapped, outbuildings demolished.
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F2
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113-157 mph
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CONSIDERABLE
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Roofs torn off frame houses, mobile homes destroyed, and trees are snapped or uprooted.
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F3
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158-206 mph
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SEVERE
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Roofs and walls off well constructed homes, trains overturned, cars thrown, most trees uprooted.
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F4
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207-260 mph
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DEVASTATING
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Homes leveled, cars thrown, structures and large debris carried some distance.
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F5
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261-318 mph
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INCREDIBLE
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Strong homes cleaned to foundation, auto sized missiles, some engineered structures blown down.
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Definitions and Introduction | What Causes Tornadoes? | How Do Tornadoes Form? | Characteristics of Tornadoes | Tornado Myths
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