Saffir-Simpson Hurricane Scale
The
Saffir-Simpson Hurricane Scale is a scale classifying most
Western Hemisphere tropical cyclones that exceed the levels of "tropical depression" and "tropical storm" and thereby become hurricanes; the "categories" it divides hurricanes into are distinguished by the intensities of their respective sustained
winds. The classifications are intended primarily for use in gauging the likely damage and
flooding a hurricane will cause upon landfall. The Saffir-Simpson Hurricane Scale is used
only to describe hurricanes forming in the
Atlantic Ocean and northern
Pacific Ocean east of the
International Date Line. Other areas label their tropical cyclones as "cyclones" and "typhoons", and use their own
classification schemes.
The scale was developed in
1969 by
civil engineer Herbert Saffir and
Bob Simpson, at that time the director of the
U.S. National Hurricane Center.
The initial scale was developed by Saffir while on commission from the
United Nations to study low-cost housing in hurricane-prone areas. While performing the study, Saffir realized there was no simple scale for describing the likely effects of a hurricane. Knowing the utility of the
Richter magnitude scale in describing earthquakes, he devised a 1–5 scale based on
wind speed that showed expected damage to structures. Saffir gave the scale to the
NHC, and Simpson added in the effects of
storm surge and flooding. The scale does not take into account
rainfall or location, which means a Category 2 hurricane that hits a major city will likely do far more damage than a Category 5 hurricane that hits a rural area.
The five categories are, in order of increasing intensity:
All wind speeds are based on a one-minute average. Central pressure values are approximate. Intensity of example hurricanes is from both the time of landfall and the maximum intensity.
There is no such category on this scale, and any mention of a Category 6 tropical cyclone is incorrect.
According to
Robert Simpson, there is no reason for a Category 6 on the Saffir-Simpson Scale because it is designed to measure the potential damage of a hurricane to man-made structures
[http://www.novalynx.com/simpson-interview.html]. If the speed of the hurricane is above 156 mph, then the damage to a building will be "serious no matter how well it's engineered". However, the result of new technologies in construction leads some to suggest that an increase in the number of categories is necessary. This suggestion was emphasized after the devastating effects of the
2005 Atlantic hurricane season. During that year
Hurricane Emily,
Hurricane Katrina,
Hurricane Rita, and
Hurricane Wilma all became Category 5 hurricanes. A few newspaper opinionists and scientists have brought up the suggestion of introducing Category 6 since then.
[http://ezinearticles.com/?Saffir-Simpson-Category-Six-Super-Hurricane-Wilma&id=84386] [http://abcnews.go.com/GMA/Science/story?id=1986862&page=1]*
Beaufort scale - For winds less intense than hurricane strength.
*
Fujita scale - For tornado intensity with damage correlated to wind speeds. The system was also intended for applicability in hurricanes and indeed is utilized by engineers in hurricane damage assessment.
*
Severe weather terminology*
Tropical cyclone*
Descriptions of the likely damage and flooding caused by each category of hurricane - The National Hurricane Center
*
An Interview with Dr. Robert Simpson - The Mariners Weather Log, April 1999
*
Q&A with Herbert Saffir - The South Florida Sun-Sentinel, June 2001
