The F scale is used to describe the intensity of tornadoes or twistas and the damage they cause. Category F0 to F4 describes damaging range from lite to devastating, however category F5 describes totally damage, framed houses are lifted from their foundation and carried miles away, automobile fly through the air like missiles, trees are uprooted, reinforced concrete structures are destroyed. For more info on hurricane Category One through Five - Explanation of what Hurricane Category Means
http://travelwithkids.about.com/od/caribbeanvacations/a/Hurricane-Category-Explained.htm
Sent from my BlackBerry® wireless device