Tornadoes - Severe Convective Storms and Tornadoes: Observations and Dynamics - page 307

Figure 6.2c. As Figure 6.2b, but near Canadian, TX, May 7, 1986, dissipating stage,
condensation aloft separating from condensation just above the ground (top); as in previous
image, but slightly later when condensation funnel aloft has completely disappeared (bottom)
(photographs by the author).
(18-32m s 1 ; 40-72mph) to F5 (117-142m s 1 ; 261-318mph), but is not cali-
brated (i.e., the relationship between wind speed and the nature of the damage
inflicted has not actually been measured under controlled conditions). The Fujita
scale was replaced by the ''Enhanced Fujita (EF) scale'' in 2007; unlike the
F-scale, it is calibrated to some extent or at least made more consistent ( Table
6.1 ). When tornadoes strike sparsely populated rural areas with little vegetation, it
becomes very dicult, if not impossible, to estimate tornado wind speeds based on
damage alone.
Damage from tornadic winds comes from the pressure exerted by the wind
(proportional to the square of the wind speed), by transient responses to wind