The Saffir-Simpson Hurricane Scale
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The Saffir-Simpson Hurricane Scale is a 1-5 rating based on the
hurricane's present intensity. This is used to give an estimate of the
potential property damage and flooding expected along the coast from a
hurricane landfall. Wind speed is the determining factor in the scale,
as storm surge values are highly dependent on the slope of the
continental shelf and the shape of the coastline, in the landfall
region. Note that all winds are using the U.S. 1-minute average.
Category One Hurricane:
Winds 74-95 mph (64-82 kt or 119-153 km/hr). Storm surge generally 4-5
ft above normal. No real damage to building structures. Damage
primarily to unanchored mobile homes, shrubbery, and trees. Some
damage to poorly constructed signs. Also, some coastal road flooding
and minor pier damage. Hurricane Lili of 2002 made landfall on the
Louisiana coast as a Category One hurricane. Hurricane Gaston of 2004
was a Category One hurricane that made landfall along the central
South Carolina coast.
Category Two Hurricane:
Winds 96-110 mph (83-95 kt or 154-177 km/hr). Storm surge generally
6-8 feet above normal. Some roofing material, door, and window damage
of buildings. Considerable damage to shrubbery and trees with some
trees blown down. Considerable damage to mobile homes, poorly
constructed signs, and piers. Coastal and low-lying escape routes
flood 2-4 hours before arrival of the hurricane center. Small craft in
unprotected anchorages break moorings. Hurricane Frances of 2004 made
landfall over the southern end of Hutchinson Island, Florida as a
Category Two hurricane. Hurricane Isabel of 2003 made landfall near
Drum Inlet on the Outer Banks of North Carolina as a Category 2
hurricane.
Category Three Hurricane:
Winds 111-130 mph (96-113 kt or 178-209 km/hr). Storm surge generally
9-12 ft above normal. Some structural damage to small residences and
utility buildings with a minor amount of curtainwall failures. Damage
to shrubbery and trees with foliage blown off trees and large trees
blown down. Mobile homes and poorly constructed signs are destroyed.
Low-lying escape routes are cut by rising water 3-5 hours before
arrival of the center of the hurricane. Flooding near the coast
destroys smaller structures with larger structures damaged by
battering from floating debris. Terrain continuously lower than 5 ft
above mean sea level may be flooded inland 8 miles (13 km) or more.
Evacuation of low-lying residences with several blocks of the
shoreline may be required. Hurricanes Jeanne and Ivan of 2004 were
Category Three hurricanes when they made landfall in Florida and in
Alabama, respectively.
Category Four Hurricane:
Winds 131-155 mph (114-135 kt or 210-249 km/hr). Storm surge generally
13-18 ft above normal. More extensive curtainwall failures with some
complete roof structure failures on small residences. Shrubs, trees,
and all signs are blown down. Complete destruction of mobile homes.
Extensive damage to doors and windows. Low-lying escape routes may be
cut by rising water 3-5 hours before arrival of the center of the
hurricane. Major damage to lower floors of structures near the shore.
Terrain lower than 10 ft above sea level may be flooded requiring
massive evacuation of residential areas as far inland as 6 miles (10
km). Hurricane Charley of 2004 was a Category Four hurricane made
landfall in Charlotte County, Florida with winds of 150 mph. Hurricane
Dennis of 2005 struck the island of Cuba as a Category Four hurricane.
Category Five Hurricane:
Winds greater than 155 mph (135 kt or 249 km/hr). Storm surge
generally greater than 18 ft above normal. Complete roof failure on
many residences and industrial buildings. Some complete building
failures with small utility buildings blown over or away. All shrubs,
trees, and signs blown down. Complete destruction of mobile homes.
Severe and extensive window and door damage. Low-lying escape routes
are cut by rising water 3-5 hours before arrival of the center of the
hurricane. Major damage to lower floors of all structures located less
than 15 ft above sea level and within 500 yards of the shoreline.
Massive evacuation of residential areas on low ground within 5-10
miles (8-16 km) of the shoreline may be required. Only 3 Category Five
Hurricanes have made landfall in the United States since records
began: The Labor Day Hurricane of 1935, Hurricane Camille (1969), and
Hurricane Andrew in August, 1992. The 1935 Labor Day Hurricane struck
the Florida Keys with a minimum pressure of 892 mb--the lowest
pressure ever observed in the United States. Hurricane Camille struck
the Mississippi Gulf Coast causing a 25-foot storm surge, which
inundated Pass Christian. Hurricane Andrew of 1992 made landfall over
southern Miami-Dade County, Florida causing 26.5 billion dollars in
losses--the costliest hurricane on record. In addition, Hurricane
Gilbert of 1988 was a Category Five hurricane at peak intensity and is
the strongest Atlantic tropical cyclone on record with a minimum
pressure of 888 mb.
Note: Some of this information has not been updated. |
