With the recent tornado outbreaks you are likely hearing that Tornados are rated "EF-1 or EF-2" as opposed to "F-1 or F-2." In February 2007 The National Weather Service implemented the "Enhanced Fujita Scale" in place of the original "Fujita Scale." The purpose of updating the scale was to more accurately and uniformly categorize tornado damage.
It is very important to understand that the scale is a damage scale, not a wind scale. Winds speeds are only estimated.
Instead of typing up everything about the enhanced scale here, we'd like to send you directly to The National Weather Service websites with all of the details. The first website below shows you the actual scales. The scale currently in use is in the far right hand column.
If would like to learn even more about how these scales were developed, head to this website:
Hopefully we won't talk too much more about the Enhanced Fujita Scale. Unfortunately though we are quickly approaching the Spring severe weather season across the country and you will likely hear more reports about "EF" storms.