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| Beaufort 1 | Beaufort 2 | Beaufort 3 |
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| Beaufort 1 | Beaufort 2 | Beaufort 3 |
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B# 0 - I assume you can guess what this looks like. B# 1- the flag only occasionally flips open, the outer end hangs lower. B# 2- the flag is mostly extended, the waves are deep, a large portion of the outer top corner flips back and forth. B# 3- the flag is completely extended, the waves are faster and smaller than 2 Bft. B# 4 & Up- the flag is still completely extended, the waves are faster than 3 Bft. The changes from 4 Bft. and up are more subtile and harder to distinguish from each other. |
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Beaufort: A Wind Scale
The Beaufort Wind Scale categorizes wind speed up to hurricane strength. The Beaufort Wind Scale categorizes various wind speeds up to hurricane strength (74 miles per hour) and is used in weather forecasting. The scale is named after its creator, Admiral Sir Francis Beaufort of the British Navy, who developed it in the early 1800's. It is still used heavily today, primarily with maritime forecasts. The 13-point scale, from 0 to 12, defines breezes, gales and hurricane force winds and also gives information on how various wind speeds affect land and sea. The number assigned to a wind speed category is called the "Beaufort Number". This number also indicates the wind's characteristics and possible damaging effects. A Beaufort (B#) of "0" means that the wind is blowing at less than one mile per hour. This is defined as "calm". Smoke rises vertically and the sea is still. The Beaufort Number 1 signifies a wind speed of one to three m.p.h. This is considered a "light air". At sea, you could expect to see ripples in the water, but no waves large enough to form foam crests. No significant effects on land occur at this stage. Smoke slants and is carried by the wind. B# 2, with winds four to seven m.p.h., defines a light breeze. Still no significant effects can be noticed on land, but at sea, the ripples turn into small wavelets. B# 3 signifies winds of eight to 12 m.p.h. This is a gentle breeze, creating small whitecaps on the ocean water. The wind is now strong enough to extend flags. B# 4 is a moderate breeze, with a wind speed of 13 to 18 m.p.h. This wind is strong enough to lift small leaves and twigs off the ground and move small branches on trees. This wind also creates small waves in the ocean with numerous whitecaps. B# 5, with winds of 19 to 24 m.p.h., is a fresh breeze. This wind produces moderate waves out in the ocean with some spray. Small trees begin to sway. B# 6, with winds of 25 to 31 m.p.h., is a strong breeze. Large waves form in the ocean with abundant white caps and a lot of spray. On land, large branches on trees sway. This type of wind is also associated with the average thunderstorm or squall line on land. B# 7 signifies winds of 32-38 m.p.h. This is defined as a moderate gale. The wind is strong enough to make entire trees sway and it begins to become difficult for a person to walk around outside, against the wind. In the ocean, large waves are splashed around and the spray is thicker and feels like large raindrops. The term "gale" is only used in marine meteorology. On land, this wind speed would be considered a strong wind, the type most usually associated with severe thunderstorms and tropical cyclones. This is also the time when a gale warning is put up. This is done by the posting of a square flag is all black with a red square in the middle. B# 8, a fresh gale with winds of 39 to 46 m.p.h., also signifies tropical storm force winds. Twigs and small branches are broken off trees. Out on the water, larger and higher waves develop. To warn sailors of this potentially hazardous wind, a tropical storm flag is put up. This flag is very similar to the gale warning flag, only the colors are reversed. B# 9, with winds of 47 to 54 m.p.h., is a strong gale. The sea begins to roll and dense streaks of foam and spray are blown about, reducing visibility. On land, slight structural damage may occur. The wind is strong enough to blow off portions of slated roofs. B# 10 is a whole gale, with wins 55 to 63 m.p.h. At this point, the waves are very high with overhanging crests. The sea begins to look whiter because of all the foam, and visibility is reduced even more. On land, the wind is strong enough to break large branches off trees and knock down small to medium-sized trees. B# 11 signifies winds 64 to 72 m.p.h. These are storm winds that create exceptionally high waves. The ocean is now covered with white foam patched. On land, widespread moderate damage could be expected. Strong tropical storms with winds of this strength have been known to create waves of six to 10 feet. B# 12, with winds above 73 m.p.h., signifies hurricane-force winds. At sea, the air is filled with foam and the ocean appears completely white from foam and spray, greatly reducing visibility. On land, the winds are violent and widespread destruction can be expected. Trees and power lines are downed. Twigs and other small, light objects become projectiles, causing damage to property. Winds faster than 73 m.p.h., hurricane force, are measured on the Saffir-Simpson Scale.  Saffir-Simpson Scale 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 in the landfall region. Category One 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. Hurricanes Allison of 1995 and Danny of 1997 were Category One hurricanes at peak intensity. Category Two 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 Bertha of 1996 was a Category Two hurricane when it hit the North Carolina coast, while Hurricane Marilyn of 1995 was a Category Two Hurricane when it passed through the Virgin Islands. Category Three 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 tress 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 hurricane center. Flooding near the coast destroys smaller structures with larger structures damaged by battering of 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 Roxanne of 1995 and Fran of 1996 were Category Three hurricanes at landfall on the Yucatan Peninsula of Mexco and in North Carolina, respectively. Category Four 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 hurricane center. 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 Luis of 1995 was a Category Four hurricane while moving over the Leeward Islands. Hurricanes Felix and Opal of 1995 also reached Catgeory Four status at peak intensity. Category Five 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 destructon 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 hurricane center. 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. There were no Category Five hurricanes in 1995, 1996, or 1997. Hurricane Gilbert of 1988 was a Category Five hurricane at peak intensity and is the strongest Atlantic tropical cyclone of record. |
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