Since tornadoes are so elusive and so violent, it's almost impossible to get accurate wind speeds from inside the funnel.
So scientists have developed a scale that allows an estimate of a tornado's wind speed by examining the damage left behind.
That scale is called the Enhanced Fujita Scale, and it classifies tornado damage from EF0 (light damage) to EF5 (total destruction).
EF0 (65-85mph) - Light damage. Minor damage to roofs or gutters. Tree branches broken off, and some smaller trees blown over.
EF1 (86-110mph) - Moderate damage. Roofs stripped. Mobile homes flipped over. Significant window/glass damage.
EF2 (111-135mph) - Considerable damage. Mobile homes destroyed. Roofs blown off well-built homes. Large trees uprooted.
EF3 (136-165mph) - Severe damage. Large buildings (shopping centers) heavily damaged. Entire stories of well-built homes blown away. Cars lifted and thrown.
EF4 (166-200mph) - Devestating damage. Well-constructed houses reduced to rubble.
EF5 (over 200mph) - Total destruction. Well-built homes blown away from their foundations. Cars thrown hundreds of feet. High-rise buildings suffer structural damage.
Thankfully, research shows that more than half of all tornadoes are EF-0. Fewer than 1 in 1,000 reach EF-5 strength, which approximates about 1 EF-5 tornado per year in the U.S.
