codyg1985’s Think Tank

The National Weather Service is changing the Fujita scale to reflect the fact that weaker winds than previously thought can topple homes and turn ordinary objects into projectiles.

An F-5 tornado under the enhanced Fujita scale would have winds of at least 200 mph instead of 261 mph.

A note from the official website:

The Enhanced F-scale still is a set of wind estimates (not measurements) based on damage. Its uses three-second gusts estimated at the point of damage based on a judgment of 8 levels of damage to the 28 indicators listed below. These estimates vary with height and exposure. Important: The 3 second gust is not the same wind as in standard surface observations. Standard measurements are taken by weather stations in open exposures, using a directly measured, “one minute mile” speed.

The new system will go into effect Feburary 2007.