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|Five|| ≥70 m/s, ≥137 knots|
≥157 mph, ≥252 km/h
|Four|| 58–70 m/s, 113–136 knots|
130–156 mph, 209–251 km/h
|Three|| 50–58 m/s, 96–112 knots|
111–129 mph, 178–208 km/h
|Two|| 43–49 m/s, 83–95 knots|
96–110 mph, 154–177 km/h
|One|| 33–42 m/s, 64–82 knots|
74–95 mph, 119–153 km/h
| 18–32 m/s, 34–63 knots|
39–73 mph, 63–118 km/h
| ≤17 m/s, ≤33 knots|
≤38 mph, ≤62 km/h
The Saffir–Simpson hurricane wind scale (SSHWS), formerly the Saffir–Simpson hurricane scale (SSHS), classifies hurricanes –Western Hemisphere tropical cyclones that exceed the intensities of tropical depressions, and tropical storms – into five categories distinguished by the intensities of their sustained winds. To be classified as a hurricane, a tropical cyclone must have maximum sustained winds of at least 74 mph (33 m/s; 64 kn; 119 km/h) (Category 1). The highest classification in the scale, Category 5, is reserved for storms with winds exceeding 156 mph (70 m/s; 136 kn; 251 km/h).
The classifications can provide some indication of the potential damage and flooding a hurricane will cause upon landfall.
Officially, the Saffir–Simpson hurricane wind 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 scales to label these storms, which are called "cyclones" or "typhoons", depending on the area.
There is some criticism of the SSHS for not taking rain, storm surge, and other important factors into consideration, but SSHS defenders say that part of the goal of SSHS is to be straightforward and simple to understand.
The scale separates hurricanes into five different categories based on wind. The U.S. National Hurricane Center classifies hurricanes of Category 3 and above as major hurricanes, and the Joint Typhoon Warning Center classifies typhoons of 150 mph or greater (strong Category 4 and Category 5) as super typhoons (although all tropical cyclones can be very dangerous). Most weather agencies use the definition for sustained winds recommended by the World Meteorological Organization (WMO), which specifies measuring winds at a height of 33 ft (10.1 m) for 10 minutes, and then taking the average. By contrast, the U.S. National Weather Service, Central Pacific Hurricane Center and the Joint Typhoon Warning Center defines sustained winds as average winds over a period of one minute, measured at the same 33 ft (10.1 m) height. Central pressure and storm surge values are approximate and often dependent on other factors, such as the size of the storm and the location. Intensity of example hurricanes is from both the time of landfall and the maximum intensity. As a result, it is not uncommon for a pressure to be significantly higher or lower than expected for a specific category. Generally, large storms with very large radii of maximum winds have the lowest pressures relative to its intensity.
The scale is roughly logarithmic in wind speed, and the top wind speed for Category "c" (c=1 to 4) can be expressed as 83x10^(c/15) miles per hour rounded to the nearest multiple of 5 – except that after the change mentioned above, Category 4 is now widened by 1 mph in each direction.
The five categories are, in order of increasing intensity:
| ≥ 33–42 m/s|
≥ 64–82 kn
≥ 119–153 km/h
≥ 74–95 mph
Hurricane Alex at peak intensity near the Azores.
Very dangerous winds will produce some damage
Category 1 storms usually cause no significant structural damage to most well-constructed permanent structures; however, they can topple unanchored mobile homes, as well as uproot or snap numerous trees. Poorly attached roof shingles or tiles can blow off. Coastal flooding and pier damage are often associated with Category 1 storms. Power outages are typically widespread to extensive, sometimes lasting several days. Even though it is the least intense type of hurricane, the storm can still produce widespread damage and can be a life-threatening storm.
Examples of storms which made landfall at this intensity include, Danny (1985), Jerry (1989), Hernan (1996), Claudette (2003), Gaston (2004), Humberto (2007), Isaac (2012), Barbara (2013), Earl (2016), Hermine (2016) and Newton (2016).
| ≥ 43–49 m/s|
≥ 83–95 kn
≥ 154–177 km/h
≥ 96–110 mph
Juan in 2003 approaching Nova Scotia
Extremely dangerous winds will cause extensive damage
Storms of Category 2 intensity often damage roofing material (sometimes exposing the roof) and inflict damage upon poorly constructed doors and windows. Poorly constructed signs and piers can receive considerable damage and many trees are uprooted or snapped. Mobile homes, whether anchored or not, are typically damaged and sometimes destroyed, and many manufactured homes also suffer structural damage. Small craft in unprotected anchorages may break their moorings. Extensive to near-total power outages and scattered loss of potable water are likely, possibly lasting many days.
| ≥ 50–58 m/s|
≥ 96–112 kn
≥ 178–208 km/h
≥ 111–129 mph
Hurricane Gaston at peak.
Devastating damage will occur
Tropical cyclones of Category 3 and higher are described as major hurricanes in the Atlantic or Eastern Pacific basins. These storms can cause some structural damage to small residences and utility buildings, particularly those of wood frame or manufactured materials with minor curtain wall failures. Buildings that lack a solid foundation, such as mobile homes, are usually destroyed, and gable-end roofs are peeled off. Manufactured homes usually sustain severe and irreparable damage. Flooding near the coast destroys smaller structures, while larger structures are struck by floating debris. A large number of trees are uprooted or snapped, isolating many areas. Additionally, terrain be flooded well inland. Near-total to total power loss is likely for up to several weeks and water will likely also be lost or contaminated.
| ≥ 58–70 m/s|
≥ 113–136 kn
≥ 209–251 km
≥ 130–156 mph
Gustav at Cuban landfall.
Catastrophic damage will occur
Category 4 hurricanes tend to produce more extensive curtainwall failures, with some complete structural failure on small residences. Heavy, irreparable damage and near complete destruction of gas station canopies and other wide span overhang type structures are common. Mobile and manufactured homes are often flattened. Most trees, except for the heartiest, are uprooted or snapped, isolating many areas. These storms cause extensive beach erosion, while terrain may be flooded far inland. Total and long-lived electrical and water losses are to be expected, possibly for many weeks.
The Galveston Hurricane of 1900, the deadliest natural disaster to hit the United States, peaked at an intensity that corresponds to a modern-day Category 4 storm. Other examples of storms making landfall at this intensity include Hazel (1954), Flora (1963), Cleo (1964), Frederic (1979), Joan (1988), Iniki (1992), Luis (1995), Charley (2004), Dennis, and Gustav (2008).
| ≥ 70 m/s|
≥ 137 kn
≥ 252 km/h
≥ 157 mph
Patricia hours after peak intensity.
Catastrophic damage will occur
Category 5 is the highest category a tropical cyclone can attain in the Saffir–Simpson scale. These storms cause complete roof failure on many residences and industrial buildings, and some complete building failures with small utility buildings blown over or away. Collapse of many wide-span roofs and walls, especially those with no interior supports, is common. Very heavy and irreparable damage to many wood frame structures and total destruction to mobile/manufactured homes is prevalent. Only a few types of structures are capable of surviving intact, and only if located at least 3 to 5 miles (5 to 8 km) inland. They include office, condominium and apartment buildings and hotels that are of solid concrete or steel frame construction, public multi-story concrete parking garages, and residences that are made of either reinforced brick or concrete/cement block and have hipped roofs with slopes of no less than 35 degrees from horizontal and no overhangs of any kind, and if the windows are either made of hurricane-resistant safety glass or covered with shutters. Unless all of these requirements are met, the absolute destruction of a structure is certain.
The storm's flooding causes major damage to the lower floors of all structures near the shoreline, and many coastal structures can be completely flattened or washed away by the storm surge. Virtually all trees are uprooted or snapped and some may be debarked, isolating most communities impacted. Massive evacuation of residential areas may be required if the hurricane threatens populated areas. Total and extremely long-lived extensive power outages and water losses are to be expected, possibly for up to several months.
Historical examples of storms that made landfall at Category 5 status include Camille (1969), Anita (1977), David (1979), Gilbert (1988), Andrew (1992), Dean (2007), and Felix (2007). No Category 5 hurricane is known to have made landfall as such in the eastern Pacific basin.