User blog:SilentShadow87/What Makes an EF5 an EF5?

Since we're trying to clean the wiki up a bit, and deleting tornadoes that users have rated EF5 without any explanation (which is understandable, who wouldn't want to have an EF5 in their hypothetical outbreak?) I thought I'd make a tutorial post explaining to new users what exactly gives a tornado an EF5 rating. Under the current Enhanced Fujita scale, there are several criteria which can be used in an EF5 rating (although none of them qualify an EF5 rating on their own; there usually need to be at least three).
 * 1) Well-constructed and anchor-bolted houses are cleanly swept away.
 * 2) Multi-story buildings are demolished or severely damaged.
 * 3) Cars and trucks are thrown more than 300 feet/90 meters
 * 4) Deep and/or widespread ground scouring and removal of grass or crops
 * 5) Highly visible wind-rowing and fine granulation of debris
 * 6) High fatality-to-injury ratios
 * 7) "Incredible Phenomena"

Well-built houses swept away
This one is actually a bit tricky, because a swept-away house doesn't necessarily mean EF5 damage on its own. The house needs to be a) well-built and b) anchor-bolted to its foundation instead of being anchored with nails or rods. Also, if the foundation is bare but debris has been pushed off the foundation and left in a pile right next to it, that's high-end EF4 damage (although sometimes the debris from houses gets mixed together, confusing the issue). If the house has a basement, another thing to look for is the appearance of the basement walls. If the basement walls at the point where the house was swept away look uneven and rough, it might not be EF5 damage without context (i.e. other EF5 damage indicators nearby); the "signature" of an EF5 being that the basement walls are left clean.

To the left you can see a photo of EF5 damage from the Moore, Oklahoma tornado on May 20, 2013. (The debris seen on the left side of the photo came from another building, not the one in the photo).

Multi-story buildings demolished or severely damaged
If a building 4 stories high or bigger is demolished or heavily damaged, that's a good indicator of a very violent tornado, probably EF5. Brick buildings can be demolished or completely leveled, while concrete and steel buildings, like the St. John's Regional Medical Center hospital in Joplin, Missouri, have interior walls demolished, ceilings collapsed or torn out, and roofing loss. No EF5 tornado, under the Enhanced Fujita scale, has ever hit a skyscraper, but the expected damage involves the building being completely stripped of its glass with the steel framework warped and twisted, and possibly shifted slightly off of its foundation. Tim Marshall supposedly said in an interview that an extreme "super-tornado" could, theoretically, twist a glass and steel skyscraper off its foundation and topple it.

On the right is a photo of EF5 damage to St. John's Regional Medical Center in Joplin, Missouri from the May 22, 2011 tornado.