Developed in the early 1970’s by Herbert Saffir, a civil engineer, and Dr. Robert Simpson of the National Hurricane Center, the scale classifies hurricanes into five categories based on the strength of their sustained winds. Each category is considered an estimate of the potential damage that a storm will cause if it makes landfall. As conditions change within a storm, its category is re-assessed.
The different categories, 1 through 5, represent increasing wind speeds and escalating degrees of damage. Storms rated category 3 or higher are considered major hurricanes. The last category 5 storm to make landfall in the US was Hurricane Andrew in 1992.
While a useful tool, the Saffir-Simpson scale does not tell the whole story of the dangers to life and property posed by a hurricane. Regardless of category, these storms can produce dangerous storm surges in coastal areas and flooding rains further inland. Recent examples of these types of impacts were seen during Sandy and Harvey, respectively.