NCDC: Satellite Events Art Gallery: Educational Topics

Hurricanes can be fickle beasts with the observed or potential damage ranging from relatively minimal to catastrophic. The damage is dependent upon several factors. Not only is the intensity of the storm important, but geophysical factors such as the size of the storm and it's associated windfield, surrounding synoptic weather situation, coastal geological features, and the astronomical tide situation play an important part. The second major portion of the "equation for disaster" is the extent of economic, industrial, and residential development of the area affected.

Following numerous on-site investigations of hurricane damage, especially that from Hurricane Camille, Herbert Saffir devised a five-category damage scale in the early 1970's. The scale had the advantage of relating ranges of sustained winds to effects on vegetation and structures. Robert Simpson, a former director of the National Hurricane Center, added additional reference to expected storm surge (the rise of a body of water above astronomical tide due to a tropical cyclone).

In 1972, the Tropical Prediction Center (then known as the National Hurricane Center) adopted the Saffir/Simpson Hurricane Scale to relate hurricane intensity and damage potential. This scale (see table below) uses the storm surge, central pressure, and/or the maximum sustained winds to classify Atlantic hurricanes into one of five categories.

Wind Speed
--------
Storm Surge

Equivalent
Fujita Scale*
--------
Central Pressure

Typical Effects

Category One Hurricane -- Weak

74-95 mph (64-82kt)

F1.0 - F1.4

Minimal Damage: Damage is primarily to shrubbery, trees, foliage, and unanchored mobile homes. No real damage occurs in building structures. Some damage is done to poorly constructed signs.

4-5 ft (1.2-1.5m)

Greater than 980 mb (28.94 in)

Low-lying coastal roads are inundated, minor pier damage occurs, some small craft in exposed anchorages torn from moorings.

Category Two Hurricane -- Moderate

96-110 mph (83-95kt)

F1.5 - F1.9

Moderate Damage: Considerable damage is done to shrubbery and tree foliage, some trees are blown down. Major structural damage occurs to exposed mobile homes. Extensive damage occurs to poorly constructed signs. Some damage is done to roofing materials, windows, and doors; no major damage occurs to the building integrity of structures.

6-8 ft (1.8-2.4m)

965-979 mb (28.50-28.91 in)

Coastal roads and low-lying escape routes inland may be cut by rising water 2-4 hours BEFORE the hurricane center arrives. Considerable pier damage occurs, marinas are flooded. Small craft in unprotected anchorages torn from moorings. Evacuation of some shoreline residences and low-lying island areas is required.

Category Three Hurricane -- Strong

111-130 mph (96-113kt)

F2.0 - F2.4

Extensive damage: Foliage torn from trees and shrubbery; large trees blown down. Practically all poorly constructed signs are blown down. Some damage to roofing materials of buildings occurs, with some window and door damage. Some structural damage occurs to small buildings, residences and utility buildings. Mobile homes are destroyed. There is a minor amount of failure of curtain walls (in framed buildings).

9-12 ft (2.7-3.7m)

945-964mb (27.91-28.47in)

Serious flooding occurs at the coast with many smaller structures near the coast destroyed. Larger structures near the coast are damaged by battering waves and floating debris. Low-lying escape routes inland may be cut by rising water 3-5 hours BEFORE the hurricane center arrives. Flat terrain 5 feet (1.5 m) or less above sea level flooded inland 8 miles or more. Evacuation of low-lying residences within several blocks of shoreline may be required.

Category Four Hurricane -- Very Strong

131-155 mph (114-135kt)

F2.5 - F2.9

Extreme Damage: Shrubs and trees are blown down; all signs are down. Extensive roofing material and window and door damage occurs. Complete failure of roofs on many small residences occurs, and there is complete destruction of mobile homes. Some curtain walls experience failure.

13-18 ft (3.9-5.5m)

920-944mb (27.17-27.88in)

Flat terrain 10 feet (3 m) or less above sea level flooded inland as far as 6 miles (9.7 km). Major damage to lower floors of structures near the shore due to flooding and battering by waves and floating debris. Low-lying escape routes inland may be cut by rising water 3-5 hours BEFORE the hurricane center arrives. Major erosion of beaches occurs. Massive evacuation of ALL residences within 500 yards (457 m) of the shoreline may be required, and of single-story residences on low ground within 2 miles (3.2 km) of the shoreline.

Category Five Hurricane** -- Devastating

Greater than
155 mph (135kt)

Greater than
F3.0

Catastrophic Damage: Shrubs and trees are blown down; all signs are down. Considerable damage to roofs of buildings. Very severe and extensive window and door damage occurs. Complete failure of roof structures occurs on many residences and industrial buildings, and extensive shattering of glass in windows and doors occurs. Some complete buildings fail. Small buildings are overturned or blown away. Complete destruction of mobile homes occurs.

Greater than
18 ft (5.5m)

Less than 920mb<27.17IN)

Major damage occurs to lower floors of all structures located less than 15 ft (4.6 m) above sea level and within 500 yards (457 m) of the shoreline. Low-lying escape routes inland are cut by rising water 3-5 hours BEFORE the hurricane center arrives. Major erosion of beaches occurs. Massive evacuation of residential areas on low ground within 5 to 10 MILES (8-16 km) of the shoreline may be required!

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Last Updated Monday, 31-Jul-2006 16:01:38 EDT by Sam.Mccown@noaa.gov
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The Saffir/Simpson Hurricane Scale

The Saffir / Simpson Hurricane Intensity Categories