The scale
| Cyclone class | Winds in km / h | Winds in kts |
|---|---|---|
| Tropical Depression | 0 - 62 | 0 - 33 |
| Tropical storm | 63 - 118 | 34 - 63 |
| Hurricane Cat. 1 | 119 - 153 | 64 - 82 |
| Hurricane Cat. 2 | 154 - 177 | 83 - 95 |
| Hurricane Major Cat. 3 | 178 - 208 | 96 - 112 |
| Hurricane Major Cat. 4 | 209 - 251 | 113 - 136 |
| Hurricane Major Cat. 5 | more 251 | more 136 |
History
Created in 1969 by 2 meteorologists (at the request of theWorld Meteorological Organization) including the former director of nhc, the Saffir-Simpson scale makes it possible to classify the power of hurricanes according to the speed of their winds.
This classification was initially intended to determine the damage that could be caused to the population and infrastructure.
It only applies to certain basins including the Atlantic basin (roughly it is applied west of 0 ° longitude to 180 ° longitude.
The wind strength for the Saffir-Simpson scale is taken over a period of 1 minute which smooths the gusts a lot. This explains the feeling that many people have of underestimation of the wind by the authorities.
Examples
Tropical Depression
Tropical storm
Hurricane Category 1
Hurricane Category 2
Hurricane Category 3
Hurricane Category 4
Hurricane Category 5
Controversy on the Saffir-Simpson scale
The 2005 season was a pivotal moment in the history of cyclones in the Atlantic. This year, both the number and the violence of the systems (Katrina on New Orleans for example) asked the question of reviewing the classification system by including, among other things, rainfalls or size. Many controversies then took place in the American scientific community on this subject, in particular on the advisability of a 6 category.
Nevertheless, the creators of the Saffir-Simpson scale felt that there was no reason to change it and that it met prevention needs very well. They relied on the idea that in any case, above 250 km / h (136 kt), a weather system was totally devastating and deadly and adding a Category 6 might make a Category 5 system appear less dangerous.
During the 2017 season, with the infamous Irma et Maria on the West Indies, the controversy has resurfaced. But as of this writing at the start of the 2020 season, no changes are planned.
Namely
There are often misunderstandings of the terms Cyclone et Hurricane.
A Tropical Cyclone indicates a tropical weather system with closed wind circulation around a low pressure center. All classes of weather systems included in the Saffir-Simpson scale are cyclones, even tropical depressions or storms.
A Hurricane is a cyclone with a wind speed greater than 118 km / h (63 kt). In hurricanes, there is also the so-called Major class for those whose wind speed exceeds 177 km / h (95 kt)
