A quick explanation of the Saffir-Simpson Wind Scale

 
Cyclone


Several conditions are required for the formation of a tropical cyclone.


These include:

  • sea surface temperatures greater than 26 degrees Celsius and more than five degrees latitude from the equator, to allow sufficient Coriolis force to initiate cyclone rotation

  • low vertical wind shear to allow massive convection unhindered by vertical wind shear (Krishnamurti et al. 2013).

The Saffir-Simpson Wind Scale is the system by which we measure potential property damage, loss of life, and overall hazards relating to a tropical cyclone. The scale has five categories, 1-5, based on a tropical cyclones maximum sustained wind speed.

Tropical cyclones with a category 3 and above are classified as ‘major’. In terms of understanding the ferocity, the hurricane that made landfall on Florida and Louisiana in 2005, Hurricane Katrina, was a category 5 hurricane.

Elsner et al. (2008) reported a rise in maximum wind speed for Atlantic tropical cyclones from 48.9 m/s to 77.8 m/s from 1981-2006, due to overall rise in sea surface temperatures - and according to the IPCC Report 2013, tropical cyclones are only expected to intensify in the future due to climate change, yet see little to no increase in frequency, or in fact a small decrease.

 
 
Cyclones
 

Sources:

  • Elsner, JB, Kossin, JP & Jagger, TH 2008, ‘The increasing intensity of the strongest tropical cyclones’, Nature Letters, vol. 455, pp. 1-4.

  • Krishnamurti, TN, Stefanova, L & Misra, V 2013, Tropical Meteorology: An Introduction, Springer, New York

  • National Oceanic and Atmospheric Administration 2012, Saffir-Simpson Hurricane Wind Scale, digital image of Saffir-Simpson hurricane wind scale, NOAA, viewed 19 September 2018, < https://www.nhc.noaa.gov/aboutsshws.php>