Hurricane Scale

All Hurricanes are dangerous, but some are more so than others. The way storm surge, wind and other factors combine determines the destructive power of a hurricane.

Saffir-Simpson Hurricane Wind Scale


To make comparisons easier and to make the predicted hazards of approaching hurricanes clearer to emergency forces, hurricane forecasters at the National Oceanic and Atmospheric Administration (NOAA) use a disaster-potential scale which assigns storms to five (5) categories, called the Saffir-Simpson Hurricane Wind Scale.

The Saffir-Simpson Scale can be used to give an estimate of the potential property damage and flooding expected along the coast as a result of hurricane activity. Each category includes wind speeds (measured on this page in miles per hour (mph)) and expected effects.

Categories


Category One
  • Wind Speed 74 - 95 mph
  • Effects: No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery, and trees. Also, some coastal road flooding and minor pier damage.
Category Two
  • Wind Speed 96 - 110 mph
  • Effect: Some roofing material, door, and window damage to buildings. Considerable damage to vegetation, mobile homes, and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of center. Small craft in unprotected anchorages break moorings.
Category Three
  • Wind Speed 111 - 130 mph
  • Effect: Some structural damage to small residences and utility buildings with a minor amount of curtain wall failures. Mobile homes are destroyed. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. Terrain continuously lower than 5 feet above sea level (ASL) may be flooded inland 8 miles or more.
Category Four
  • Wind Speed 131 – 155 mph
  • Effect: More extensive curtain wall failures with some complete roof structure failure on small residences. Major erosion of beach. Major damage to lower floors of structures near the shore. Terrain that is continuously lower than 10 feet ASL may be flooded requiring massive evacuation of residential areas inland as far as 6 miles.
Category Five
  • Wind Speed 155 mph – ?
  • Effect: Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Major damage to lower floors of all structures located less than 15 feet ASL and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5 to 10 miles of the shoreline may be required.
Source: U.S. Department of Commerce, NOAA, National Weather Service