#fotd1583

#1583: the Fujita scale for assessing the intensity of a tornado was invented in 1971, but it wasn't really properly grounded in physics - all the numbers were more or less wild guesses, and you based on consensus. they upgraded the system to the Enhanced Fujita scale, which runs very similarly, but more standardised: there are a list of 26-odd "Damage Indicators" (Canada uses 31) which are basically types of structures (bungalow, shed, fence, stuff like that) and the windspeeds at which they fall over. the main difference between the two scales is that now all these structures are standardised: a wooden fence is made of panels with posts sunk into concrete post holes in the ground, for example. measuring the amount of roof lost on a heritage churche, for example, will point towards particular wind speeds to help categorise a tornado. the first tornado to get an EF5 on the new system was the Greensburg tornado in 2007.