BEAUFORT SCALE OF WIND VELOCITY

Use these standard criteria for more accurate wind reports to
the National Weather service. The scale was devised in 1805 by
English Rear Admiral Sir Francis Beaufort (pronounced "BO-fert").
It has often been revised and updated.

NOTE: Observations should be made as far away as possible from
structures and trees, which create false wind estimates. A pocket 
compass helps to determine wind direction accurately.

Distribute this scale freely to Packet BBSs and at club
meetings and ARES and SKYWARN training sessions. Keep one copy
in your car and another at your operating desk. - W4MLE
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MPH: <1        KTS: <1  ("Dead calm") 
EFFECTS: Smoke rises vertically. Pennants hang limp and 
motionless. Sea is mirror flat. 
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MPH: 1-3       KTS: 1-3 
EFFECTS: Direction of wind shown by smoke drift. Flags and 
pennants hang limp or barely move. Ripples at sea, with 
appearance of scales, without foam crests.
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MPH: 4-7       KTS: 4-6 
EFFECTS: Wind felt on face; leaves rustle. Pennants stir 
slightly; flags may move slightly. At sea, small wavelets, 
short but pronounced; crests appear glassy and don't break. 
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MPH: 8-12      KTS: 7-10 
EFFECTS: Leaves and small twigs in constant motion. Flags flap 
partly extended. At sea, large wavelets with crests beginning to 
break; foam appears glassy. Maybe some scattered foam crests.
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MPH: 13-18     KTS: 11-16 
EFFECTS: Tree-tops sway and small branches flutter constantly; 
Dust, dead leaves and loose paper are blown about. Flags flutter 
but are not fully extended. Small pennants are fully extended. At 
sea, small waves, becoming longer; fairly frequent white caps.
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MPH: 19-24     KTS: 17-21
EFFECTS: Small trees sway and bend slightly; flags snap 
noisily. Traffic lights sway and dance on their suspensions. 
Whitecaps on inland water. At sea, moderate waves of a distinct 
long form; many white caps. Maybe some spray.
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MPH: 25-31     KTS: 22-27
EFFECTS: Large branches sway; Flags snap and pop noisily and 
stand straight out from the mast, indicating wind direction.
Traffic lights dance on their suspension cables. At sea, large 
waves begin to form; white foam crests more extensive everywhere; 
probably some spray.
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MPH: 32-38     KTS: 28-33
EFFECTS: Whole trees sway; difficult to walk against the wind. 
Lawn furniture and loose light objects may be overturned or 
blown around. Dead limbs fall from trees. Traffic lights dance 
vigorously on suspension cables. Metal traffic signs sway 
rhythmically from side to side. Sea heaps up; white foam from 
breaking waves blows in streaks along the direction of the wind. 
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MPH: 39-46     KTS: 34-40
EFFECTS: Twigs and small limbs break off of trees. Suspended 
traffic lights dance vigorously and sometimes fall. Lawn and 
deck furniture, advertising signs, tree limbs and sometimes 
trees may be blown down, blocking streets or highways. Driving 
is very hazardous. At sea moderately high waves. Edges of 
crests begin to break into spindrift. Streaks of foam blow 
down-wind. GALE WARNINGS MAY BE ISSUED BY WEATHER SERVICE
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MPH: 47-54     KTS: 41-47
EFFECTS: Slight damage to buildings; shingles are loosened or
tear free. Trees in exposed places may be uprooted, or limbs
may break off. Exposed objects may be blown about, striking
other objects or blocking streets. Drive with extreme caution, if 
at all. High waves at sea. Dense streaks of foam along direction 
of wind. Spray may affect visibility. GALE WARNINGS IN EFFECT
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MPH: 55-63     KTS: 48-55
EFFECTS: Large trees are uprooted; considerable damage to
buildings. Visibility reduced by spray. Drive only if absolutely 
necessary. Get away from the coast and seek shelter inland and 
out of wind. At sea, very high waves with long overhanging 
crests; great patches of foam blown in dense white streaks along 
direction of wind. Sea surface takes on a white appearance.
GALE WARNINGS IN EFFECT. STORM WARNINGS MAY BE ISSUED.
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MPH: 64-72     KTS: 56-63
EFFECTS: Widespread damage on land. Wind-driven advertising 
signs, lawn and deck furniture begin to fly through the air. At 
sea, exceptionally high waves completely covered with long white 
patches of foam lying along direction of wind; edges of wave 
crests blown into froth. Visibility at sea greatly reduced.
HURRICANE WARNINGS IN EFFECT. AVOID COASTAL AREAS. SEEK SHELTER.
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NOTE: Updated and re-calibrated September 1994 
-- 

George Thurston W4MLE, Tallahassee FL 
COMPUSERVE: 72417,2466 - INTERNET: thurston@freenet.fsu.edu