The Saffir-Simpson Hurricane Scale is used to classify storms that are stronger than "tropical depressions" and "tropical storms". The scale separates hurricanes into five different categories based on sustained wind speeds, barometric pressure, and storm surge. In order to be classified as a hurricane, a storm must have sustained winds of more than 74 mph. The highest classification in the scale, Category 5, is reserved for storms with winds greater than 155 mph. The U.S. National Hurricane Center classifies hurricanes of Category 3 and above as major hurricanes.
The classifications are intended primarily for use in measuring the potential damage and flooding a hurricane will cause upon landfall. The Saffir-Simpson Hurricane Scale is used only to describe hurricanes forming in the Atlantic Ocean and northern Pacific Ocean east of the International Date Line. Other areas use different classification scales to classify storms, which are called "cyclones" or "typhoons", depending on the area.
74–95 mph (64–82 knots)
|Minimal Damage - primarily to shrubbery, trees, foliage and mobile homes...no real wind damage to other structures. There will be some damage to poorly constructed signs. Low-lying coastal roads will flood and there will be minor pier damage and some small craft in exposed anchorage could be torn from moorings. Hurricane Erin at landfall in 1995.|
96–110 mph (83–95 kt)
|Considerable Damage - to shrubbery and tree foliage...some trees will be blown down. Mobile homes will suffer major damage. There will be extensive damage to poorly constructed signs. There will be some damage to roofs, windows and doors, but no major wind damage to buildings. Considerable damage could occur to piers and marinas could flood. Small watercraft may be torn from moorings.|
111–129 mph (96–112 kt)
|Extensive Damage - Foliage torn from trees, large trees blown down. There will be damage to roofs, windows and doors and some structural damage to small buildings. Mobile homes will be destroyed. There will be serious coastal flooding and many smaller structures near the coast will be destroyed. Larger structures near coast will be damaged by battering waves and floating debris. Hurricanes Opal (1995), Ivan (2004), and Dennis (2005), were all category 3 hurricanes when they made landfall.|
130–156 mph (113–136 kt)
|Extreme Damage - there will be extensive damage to roofs, windows and doors, complete failure of roofs on small buildings and complete destruction of mobile homes. Lower floors of structures near the coast will sustain major damage from flooding and battering by waves and floating debris. There will also be major beach erosion. Hurricane Katrina was a category 4 storm when it made landfall.|
≥157 mph (≥137 kt)
|Catastrophic Damage - massive destruction of shrubs and trees, considerable damage to roofs of buildings and all signs are damaged or destroyed. There would be complete failure of roofs on many residences and industrial buildings. Extensive shattering of glass in windows and doors would occur and some complete building failures. Small buildings would be overturned or blown away and mobile homes would be destroyed. Three Category 5 storms have hit the U.S. since record keeping began...the 1935 Labor Day hurricane that killed 405 people when it hit the Florida Keys, Hurricane Camille which devastated the Mississippi coast in 1969, killing 265 people and Hurricane Andrew which struck south Florida in 1992 causing over $25-billion dollars in damage.|