The Saffir-Simpson Scale is used to classify the intensity of hurricanes. It has been in use by the National Hurricane Center in Miami since the early 1970s. The scale was developed by Herbert Saffir and Robert Simpson.

Herbert Saffir was (and is) a structural engineer. At the time that he developed the scale, he studied the effects of wind and windstorms on structures. He actually developed most of the scale. He became involved because he was considered an expert. In 1969, the United Nations wanted a study done about the resistance of low-income housing in third world countries to hurricanes (typhoons or tropical cyclones if you prefer). During the course of his study, he realized that unlike earthquakes, there was simply no scale that existed to measure the power of hurricanes. So, he created the scale, including the measurements of wind speed and barometric pressure. He also included the measurements of possible damage to structures.

Robert Simpson was at that time the director of the National Hurricane Center. Mr. Saffir gave what he had developed to Mr. Simpson. Simpson added the information about storm surges that exist with each category.

The Scale

Category | Pressure(mmHg)| Wind Speed (mph) | Storm Surge (ft) | Damage
   1     |  > 980        |  74-95           | 4-5              |  Minimal
   2     |  965-980      |  96-110          | 6-8              |  Moderate
   3     |  945-964      |  111-130         | 9-12             |  Extensive
   4     |  920-944      |  131-155         | 13-18            |  Extreme
   5     |  < 920        |  > 155           | > 18             |  Catastrophic