The Saffir-Simpson Hurricane Wind Scale (Experimental)
The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 categorization based on the hurricane's
intensity at the indicated time. The scale provides examples of the type of damages and
impacts in the United States associated with winds of the indicated intensity. In general,
damages rise by about a factor of four for every category increase. The maximum sustained
surface wind speed (peak 1-minute wind at 10 m [33 ft]) is the determining factor in the
scale. The historical examples (one for the U.S. Gulf Coast and one for the U.S. Atlantic
Coast) provided in each of the categories correspond with the intensity of the hurricane
at the time of landfall in the location experiencing the strongest winds, which does not
necessarily correspond with the peak intensity reached by the system during its lifetime.
The scale does not address the potential for such other hurricane-related impacts, as storm
surge, rainfall-induced floods, and tornadoes. These wind-caused impacts are to apply to
the worst winds reaching the coast and the damage would be less elsewhere. It should also be
noted that the general wind-caused damage descriptions are to some degree dependent upon the
local building codes in effect and how well and how long they have been enforced. For example,
recently enacted building codes in Florida, North Carolina and South Carolina are likely
to somewhat reduce the damage to newer structures from that described below. However, for
a long time to come, the majority of the building stock in existence on the coast will not
have been built to higher code. Hurricane wind damage is also dependent upon such other
factors as duration of high winds, change of wind direction, amount of accompanying rainfall,
and age of structures.
Earlier versions of this scale - known as the Saffir-Simpson Hurricane Scale - incorporated
central pressure and storm surge as components of the categories. The central pressure was
utilized during the 1970s and 1980s as a proxy for the winds as accurate wind speed intensity
measurements from aircraft reconnaissance were not routinely available for hurricanes until
1990. Storm surge was also quantified by category in the earliest published versions of the
scale dating back to 1972. However, hurricane size (extent of hurricane force winds), local
bathymetry (depth of near-shore waters), and topographic forcing can also be important in
forecasting storm surge. Moreover, other aspects of hurricanes - such as the system's
forward speed and angle to the coast - also impact the storm surge that is produced. For
example, the very large Hurricane Ike (with hurricane force winds extending as much as 125
mi from the center) in 2008 made landfall in Texas as a Category 2 hurricane and had peak
storm surge values of 15-20 ft. In contrast, tiny Hurricane Charley (with hurricane force
winds extending at most 25 mi from the center) struck Florida in 2004 as a Category 4
hurricane and produced a peak storm surge of only 6-7 ft. These storm surge values were
substantially outside of the ranges suggested in the original scale. Thus to help reduce
public confusion about the impacts associated with the various hurricane categories as well
as to provide a more scientifically defensible scale, the storm surge ranges, flooding
impact and central pressure statements are being removed from the scale and only peak winds
are employed in this revised version - the Saffir-Simpson Hurricane Wind Scale.
- Category One Hurricane:
- Sustained winds 74-95 mph (64-82 kt or 119-153 km/hr). Damaging winds are expected. Some
damage to building structures could occur, primarily to unanchored mobile homes (mainly
pre-1994 construction). Some damage is likely to poorly constructed signs. Loose outdoor
items will become projectiles, causing additional damage. Persons struck by windborne
debris risk injury and possible death. Numerous large branches of healthy trees will
snap. Some trees will be uprooted, especially where the ground is saturated. Many areas
will experience power outages with some downed power poles. Hurricane Cindy (pdf) (2005, 75 mph
winds at landfall in Louisiana) and Hurricane Gaston (2004, 75 mph winds at landfall in
South Carolina) are examples of Category One hurricanes at landfall.
- Category Two Hurricane:
- Sustained winds 96-110 mph (83-95 kt or 154-177 km/hr). Very strong winds will produce
widespread damage. Some roofing material, door, and window damage of buildings will occur.
Considerable damage to mobile homes (mainly pre-1994 construction) and poorly constructed
signs is likely. A number of glass windows in high rise buildings will be dislodged and
become airborne. Loose outdoor items will become projectiles, causing additional damage.
Persons struck by windborne debris risk injury and possible death.. Numerous large
branches will break. Many trees will be uprooted or snapped. Extensive damage to power
lines and poles will likely result in widespread power outages that could last a few to
several days. Hurricane Erin (1995, 100 mph at landfall in northwest Florida) and Hurricane
Isabel (2003, 105 mph at landfall in North Carolina) are examples of Category Two hurricanes
at landfall.
- Category Three Hurricane:
- Sustained winds 111-130 mph (96-113 kt or 178-209 km/hr). Dangerous winds will cause
extensive damage. Some structural damage to houses and buildings will occur with a
minor amount of wall failures. Mobile homes (mainly pre-1994 construction) and poorly
constructed signs are destroyed. Many windows in high rise buildings will be dislodged
and become airborne. Persons struck by windborne debris risk injury and possible
death. Many trees will be snapped or uprooted and block numerous roads. Near total
power loss is expected with outages that could last from several days to weeks.
Hurricane Rita (pdf) (2005, 115 mph landfall in east Texas/Louisiana) and
Hurricane Jeanne
(2004, 120 mph landfall in southeast Florida) are examples of Category Three hurricanes
at landfall.
- Category Four Hurricane:
- Sustained winds 131-155 mph (114-135 kt or 210-249 km/hr). Extremely dangerous winds
causing devastating damage are expected. Some wall failures with some complete roof
structure failures on houses will occur. All signs are blown down. Complete destruction
of mobile homes (primarily pre-1994 construction). Extensive damage to doors and windows
is likely. Numerous windows in high rise buildings will be dislodged and become airborne.
Windborne debris will cause extensive damage and persons struck by the wind-blown debris
will be injured or killed. Most trees will be snapped or uprooted. Fallen trees could
cut off residential areas for days to weeks. Electricity will be unavailable for weeks
after the hurricane passes. Hurricane
Charley (2004, 145 mph at landfall in southwest
Florida) and Hurricane Hugo (1989, 140 mph at landfall in South Carolina) are examples
of Category Four hurricanes at landfall.
- Category Five Hurricane:
- Sustained winds greater than 155 mph (135 kt or 249 km/hr). Catastrophic damage is
expected. Complete roof failure on many residences and industrial buildings will occur.
Some complete building failures with small buildings blown over or away are likely. All
signs blown down. Complete destruction of mobile homes (built in any year). Severe and
extensive window and door damage will occur. Nearly all windows in high rise buildings
will be dislodged and become airborne. Severe injury or death is likely for persons
struck by wind-blown debris. Nearly all trees will be snapped or uprooted and power
poles downed. Fallen trees and power poles will isolate residential areas. Power outages
will last for weeks to possibly months. Hurricane Camille (pdf) (1969, 190 mph at landfall in
Mississippi) and Hurricane Andrew (1992, 165 mph at landfall in Southeast Florida) are
examples of Category Five hurricanes at landfall.
More details about this experimental change can be found at weather.gov/infoservicechanges/sshws.pdf
Comments about the new Saffir-Simpson Hurricane Wind Scale? Please send us an email.
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