The Saffir-Simpson Hurricane Scale is a rubric which rates hurricanes between one and five, depending on their intensity. The scale is intended to roughly predict the amount of expected damage before a hurricane hits land, allowing officials to prepare accordingly. The Saffir-Simpson Hurricane Scale is primarily used in North America, and refers to North Pacific and Atlantic hurricanes. In other parts of the world, different descriptions and scales may be used.
The design of the scale began in 1969, when Herbert Saffir was commissioned to examine the impact of hurricanes on low cost housing. While Saffir was performing his research, he realized that there was no uniform scale for describing hurricane conditions, which made it very difficult to analyze information well. He came up with a hurricane scale roughly modeled on the Richter scale, using wind speed as a guide to describe hurricanes.
Saffir submitted the hurricane scale to Bob Simpson, the director of the United States National Hurricane Center. Simpson made a few changes to the scale, incorporating the potential for storm surge as well as wind speed, and the end result was named for both men, recognizing their equal contributions. By looking at hurricanes while they are still offshore, the hurricane center can assess where they fit on the scale, thus allowing people on land to estimate how severe the damage may be. The estimates of damage severity are the result of decades of compiled data about actual damage during hurricanes.
The most mild hurricane on the scale is a category one. A category one hurricane will inflict minimal damage, potentially uprooting small trees and poorly installed signs. Mobile homes and rickety structures may also be at risk during a category one. A category five, on the other hand, has winds in excess of 156 miles per hour (250 kilometers per hour), and it will cause “severe” damage to most structures. There is no category higher than a six, since the hurricane scale is intended to predict damage, rather than quantifying severity as the Richter scale does.
Very few hurricanes reach a category five, and when they do, it tends to be an event of note. The high winds of these hurricanes are accompanied by a serious storm surge, which can cause severe flooding compounded by heavy rain. Hurricane Katrina was a well known example of a category five hurricane, as was the Labor Day hurricane of 1935 in Florida. It is highly unusual to see more than one or two category five hurricanes, although the 2005 Atlantic hurricane season proved to be the unfortunate exception to this rule.