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Difference Between an F1 & F2 Tornado

Since the early 1970s, meteorologists have classified tornadoes using a scale developed by T. Theodore Fujita. In Dr. Fujita's honor, the scale is called the Fujita Tornado Damage Scale, usually shortened to F Scale. The F Scale divides tornadoes into classes based on the severity of damage the storm causes. The weakest storms are F0 (F zero) and storms increase in power to F5. Using input from meteorologists and wind engineers, the National Weather Service adopted an Enhanced Fujita Scale, or EF Scale, in 2007. The EF Scale is based on more modern measurements of the effects of wind on natural and man-made structures.
  1. F1 Tornado

    • An F1 tornado is considered a "weak" tornado. In the original F Scale, F1 tornadoes were estimated to contain winds with maximum speed of between 73 and 112 MPH and a maximum 3-second wind gust speed of 79 to 117 MPH. The EF Scale changes the maximum 3-second gust speed to between 86 and 110 MPH. Descriptively, an F1 tornado causes moderate damage including any or all of peeling surface materials off of roofs, pushing mobile homes from their supports, lifting and moving vehicles from roads and severely damaging attached garages. Winds with velocity of at least 73 MPH are considered hurricane winds.

    F2 Tornado

    • An F2 tornado, termed a "strong" tornado, contains winds moving at higher speed and therefore has the potential to cause more severe damage than an F1 tornado. In the original F Scale, F2 tornadoes were estimated to contain winds with maximum speed of between 113 and 157 MPH with a maximum 3-second wind gust speed of 118 to 161 MPH. The EF Scale changes the maximum 3-second gust speed to between 111 and 135 MPH. Descriptively, an F2 tornado causes considerable damage. The storm can tear roofs from houses, demolish mobile homes, snap or uproot trees and turn lighter objects into missiles capable of penetrating solid surfaces.

    Stronger Storms

    • The F Scale continues to F5, the "incredible" tornado. F5 tornado winds are estimated to reach sustained speeds of 261 to 318 MPH, causing severe damage to steel-reinforced concrete structures and turning cars into air-borne missiles. Fortunately, less than 1 percent of tornadoes reach the level of F4. As of 2010, the three most recent F5 tornadoes in the USA occurred in Parkersburg, Iowa (May 25, 2008), Greensburg, Kansas (May 4, 2007), and Moore and Bridge Creek, Oklahoma (May 3, 1999).

    Wind Estimates

    • Meteorologists caution the public that the wind speeds cited in the F and EF Scales are only estimates that have not been verified by direct measurements. Wind speed is just one variable to consider when assessing damage. Other variables include the quality of the construction and the shape of the terrain near the site where a storm touches down. Given different conditions, it is possible for the same storm with the same wind speed to cause different levels of damage at two different locations.


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