In the classification of a tornado I have seen it written as F5 and EF5. Are they both right?
The Enhanced Fujita Scale, or EF Scale, is the scale for rating the strength of tornadoes in the United States estimated via the damage they cause. Implemented in place of the Fujita scale introduced in 1971, it began operational use on February 1, 2007. The scale has the same basic design as the original Fujita scale, six categories from zero to five representing increasing degrees of damage. It was revised to reflect better examinations of tornado damage surveys, so as to align wind speeds more closely with associated storm damage. Better standardizing and elucidating what was previously subjective and ambiguous, it also adds more types of structures as well as vegetation, expands degrees of damage, and better accounts for variables such as differences in construction quality. The new scale was publicly unveiled by the National Weather Service at a conference of the American Meteorological Society in Atlanta on February 2, 2006. It was developed from 2000-2004 by the Fujita Scale Enh
But from now on, they are using the EF scale. As F stood for Fujita (as in the Fujita Scale, which measured tornado strength until last year), EF stands for Enhanced Fujita (the scale that went into effect earlier this year). The biggest difference is that EF5 is lower than F5 was, but now EF5 has no maximum. Anything over 200 mph will be an EF5, wheras an F5 was 261–318 mph. So, F5 WAS the correct term for some tornadoes, but the same tornado that was an F5 is now an EF5. A little confusing, but the link helps explain it. I hope this helps! Sources: http://en.wikipedia.
