The Saffir-Simpson Scale: Understanding Hurricanes on a Richter Scale

Like the 10 point Richter Scale, the Saffir-Simpson Scale's purpose is to simplify our understanding of hurricanes using a rating system. The 1-5 scale, based upon wind speeds, tells the potential damage and impact a hurricane can have once it hits land. Since the basis for defining a hurricane on this scale is wind speed, some things such as storm surge and other effects can vary somewhat between categories.

The Saffir-Simpson was first developed in 1969 by civil engineer Herbert Saffir. He realized that unlike earthquakes, there was no common scale used to inform people about the intensity of hurricanes. Initially it was done at the behest of the United Nations who were doing a study of low-cost housing in hurricane prone areas.

After working on this project he gave his new scale to the National Hurricane Center (NHC). The director of the NHC at that time was Bob Simpson. Besides wind speed and potential damage to buildings, Simpson also added the levels of storm surge and flooding to be expected with each of the five categories of hurricanes. The Saffir-Simpson Scale was born.

Tropical Depressions and Tropical Storms

The Saffir-Simpson Scale deals with the five categories of hurricanes. However there are also other distinctions used by hurricane watchers to refer to pre-hurricane storms which they use to monitor developments in possible hurricanes.

The lowest level is a tropical depression. This involves conditions where winds are between 0 and 38 miles per hour. Thestorm surge for a tropical depression is 0 feet.

Somewhat more serious than a tropical depression is a tropical storm. When a depression becomes a tropical storm it is designated with a number. The numbers go up sequentially started at 1 every hurricane season. Tropical storms have wind speeds ranging between 39 and 73 miles per hour, with storm surges ranging between 0 and 3 feet.

Category 1 Hurricane on the Saffir-Simpson Scale