Saffir–Simpson scale
| Category | m/s | knots | mph | km/h |
|---|---|---|---|---|
| 5 | ≥ 70 | ≥ 137 | ≥ 157 | ≥ 252 |
| 4 | 58–70 | 113–136 | 130–156 | 209–251 |
| 3 | 50–58 | 96–112 | 111–129 | 178–208 |
| 2 | 43–49 | 83–95 | 96–110 | 154–177 |
| 1 | 33–42 | 64–82 | 74–95 | 119–153 |
| TS | 18–32 | 34–63 | 39–73 | 63–118 |
| TD | ≤ 17 | ≤ 33 | ≤ 38 | ≤ 62 |
The Saffir-Simpson Hurricane Scale is a scale classifying most Western Hemisphere tropical cyclones that exceed the intensities of "tropical depressions" and "tropical storms", and thereby become hurricanes. The categories into which it divides hurricanes are distinguished by the intensities of their respective sustained winds. The classifications are intended primarily for use in measuring the potential 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 scales.
History
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.[1]
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.[2]
Categories
The five categories are, in order of increasing intensity: Template:Saffir-Simpson full
The U.S. National Hurricane Center classifies hurricanes of Category 3 and above as major hurricanes. The definition of sustained winds recommended by the World Meteorological Organization (WMO) and used by most weather agencies is that of a 10-minute average at a height of 10 m (33 ft) . The U.S. weather service defines sustained winds based on 1-minute average speed, also measured 10 m (33 ft) above the surface..[3][4] Central pressure values are approximate. Intensity of example hurricanes is from both the time of landfall and the maximum intensity.[5]
Category 6
There is no such category on this scale, and any mention of a Category 6 tropical cyclone is fictitious or 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.[6] 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.[7]
See also
- 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
References
- ^ Williams, Jack (May 17, 2005). "Hurricane scale invented to communicate storm danger". USA Today. Retrieved 2007-02-25.
{{cite news}}: Check date values in:|date=(help) - ^ "Wilma's Rage Suggests New Hurricane Categories Needed: History of the Scale". LiveScience.com. 2005-10-20. Retrieved 2007-02-25.
- ^ Tropical Cyclone Weather Services Program (June 1, 2006). "Tropical cyclone definitions" (PDF). National Weather Service. Retrieved 2006-11-30.
{{cite web}}: Check date values in:|date=(help) - ^ Federal Emergency Management Agency (2004). "Hurricane Glossary of Terms". Retrieved 2006-03-24. Accessed through the Wayback Machine.
- ^ National Hurricane Center (June 22, 2006). "Saffir-Simpson Hurricane Scale Information". National Oceanic and Atmospheric Administration. Retrieved 2007-02-25.
{{cite web}}: Check date values in:|date=(help) - ^ Debi Iacovelli (2001-07). "The Saffir/Simpson Hurricane Scale: An Interview with Dr. Robert Simpson". South Florida Sun-Sentinel. Retrieved 2006-09-10.
{{cite web}}: Check date values in:|date=(help) - ^ Bill Blakemore (2006-05-21). "Category 6 Hurricanes? They've Happened:Global Warming Winds Up Hurricane Scientists as NOAA Issues Its Atlantic Hurricane Predictions for Summer 2006". ABC News. Retrieved 2006-09-10.
{{cite news}}: Check date values in:|date=(help)
External links
- 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