Saffir-Simpson Hurricane Wind Scale

On May 15, 2012, there will be minor modifications made to the Saffir-Simpson Hurricane Wind Scale Thresholds for Categories 3, 4 and 5. These changes have been reflected in the documentation below. Please see the Public Information Statement issued March 1, 2012 for more details.

The Saffir-Simpson Hurricane Wind Scale for Hawaii
The Saffir-Simpson Hurricane Wind Scale for Hawaii is a 1 to 5 categorization based on the hurricane's intensity at the indicated time.  The scale provides examples of the type of damages and impacts in Hawaii associated with winds of the indicated intensity.  In general, damages rise by about a factor of four for every category increase.  The maximum sustained surface wind speed (peak 1-minute wind at 10 m [33 ft]) is the determining factor in the scale.  The historical examples provided in each of the categories correspond with the intensity of the hurricane at the time of landfall or closest approach in the location experiencing the strongest winds, which does not necessarily correspond with the peak intensity reached by the system during its lifetime.  The scale does not address the potential for such other hurricane-related impacts as coastal inundation, waves, and storm surge, rainfall-induced floods, and tornadoes.  The wind-caused impacts are to apply to the worst winds reaching the coast and the damage would be less elsewhere.  Hurricane wind damage is also dependent upon such other factors as duration of high winds, change of wind direction, amount of accompanying rainfall, and age and strength of structures. Earlier versions of this scale - known as the Saffir-Simpson Hurricane Scale - incorporated central pressure and storm surge as components of the categories.  The central pressure was utilized during the 1970s and 1980s as a proxy for the winds as accurate wind speed intensity measurements from aircraft reconnaissance were not routinely available for hurricanes until 1990.  Storm surge was also quantified by category in the earliest published versions of the scale dating back to 1972.  However, hurricane size (extent of hurricane force winds), local bathymetry (depth of near-shore waters), and topographic forcing can also be important in forecasting the actual coastal inundation, for which storm surge is only one contributing factor in near-shore deep-water locations such as Hawaii.  Moreover, other aspects of hurricanes - such as the system's forward speed and angle to the coast - also impact the coastal inundation that is produced.  Thus, to help reduce public confusion about the impacts associated with the various hurricane categories, as well as to provide a more scientifically defensible scale, the storm surge ranges, flooding impact and central pressure statements are being removed from the scale and only peak winds are employed in this revised version - the Saffir-Simpson Hurricane Wind Scale.

More details about this experimental change can be found at http://www.weather.gov/infoservicechanges/sshws.pdf

Comments about the new Saffir-Simpson Hurricane Wind Scale? Please send us an email at W-HFO.Webmaster@noaa.gov