What Is the Saffir-Simpson Wind Scale?
The Saffir-Simpson Wind Scale is a categorical classification of hurricanes based on their wind speed, used by the U.S. government's National Hurricane Center. The scale was first used in 2009, though the wind speeds of the categories match the Saffir-Simpson Hurricane Scale (see below). The scale underwent a minor modification in 2012. The categories are Category 1, 2, 3, 4 and 5:
Category One Hurricane: Sustained winds 74-95 mph (64-82 kt or 119-153 km/hr).
Category Two Hurricane: Sustained winds 96-110 mph (83-95 kt or 154-177 km/hr).
Category Three Hurricane: Sustained winds 111-129 mph (96-112 kt or 178-208 km/hr).
Category Four Hurricane: Sustained winds 130-156mph (113-136kt or 209-251 km/hr).
Category Five Hurricane: Sustained winds greater than 156 mph (136 kt or 251 km/hr).
Detailed descriptions of the damage to be expected from each category can be found on the NHC website.
What Was the Saffir-Simpson Hurricane Scale?
From 1971 until 2008, the NHC used the Saffir-Simpson Hurricane Scale, which also utilized pressure, storm surge and flooding measurements [WikiPedia]. After Hurricane Ike in 2007, which produced a storm surge undeserving to its Category 2 status, the NHC dropped all requirements except wind "to help reduce public confusion about the impacts associated with the various hurricane categories as well as to provide a more scientifically defensible scale." You can read more about this on their website.