FORE  &  AFT  MARINE

    The Beaufort Scale of Wind Forces
    The Beaufort Scale reflects both wind strength and sea conditions. Developed in 1805 by Admiral Sir Francis Beaufort of the British Navy. The scale divides wind and sea conditions into 12 "Forces" ranging from calm to hurricane. It describes typical conditions offshore in large bodies of water.

    Beaufort Number or Force
    		 Wind Speed and Description
    		 Effects Land/Sea
    		 Probable Wave Height
    MPH
    		 Knots
    		 Description
    0
    		 <1
    		 <1
    		 Calm
    		 Still, calm air, smoke will rise vertically. Smooth like a mirror.
    		 0
    1
    		 1-3
    		 1-3
    		 Light Air
    		 Rising smoke drifts, wind vane is inactive. Small ripples like fish scales.
    		 ¼ - ½ foot
    2
    		 4-7
    		 4-6
    		 Light Breeze
    		 Leaves rustle, can feel wind on your face, wind vanes begin to move. Short, small pronounced wavelets with no crests.
    		 ¼ - ½ foot
    3
    		 8-12
    		 7-10
    		 Gentle Breeze
    		 Leaves and small twigs move, light weight flags extend. Large wavelets, crests start to break, some whitecaps.
    		 2 feet
    4
    		 13-18
    		 11-16
    		 Moderate Breeze
    		 Small branches move, raises dust, leaves and paper. Small waves develop, becoming longer, whitecaps.
    		 4 feet
    5
    		 19-24
    		 17-21
    		 Fresh Breeze
    		 Small trees sway. Moderate lengthening waves, with many white caps and some spray.
    		 6 feet
    6
    		 25-31
    		 22-27
    		 Strong Breeze
    		 Large tree branches move, telephone wires begin to "whistle"Large waves, extensive white caps, some spray.
    		 10 feet
    7
    		 32-38
    		 28-33
    		 Near Gale
    		 Large trees sway, becoming difficult to walk. Heaps of waves, with some breakers whose foam is blown downwind in streaks.
    		 14 feet
    8
    		 39-46
    		 34-40
    		 Gale
    		 Twigs and small branches are broken from trees, walking is difficult. Moderately large waves with blown foam.
    		 18 feet
    9
    		 47-54
    		 41-47
    		 Strong Gale
    		 Slight damage occurs to buildings, shingles are blown off of roofs. Rolling seas, dense foam, Blowing spray reduces visibility.
    		 23 feet
    10
    		 55-63
    		 48-55
    		 Whole Gale or Storm
    		 Trees are broken or uprooted, building damage is considerable. Very high waves with long, overhanging crests. The sea looks white, visibility is greatly reduced.
    		 29 feet
    11
    		 64-72
    		 56-63
    		 Violent Storm
    		 Extensive widespread damage. Wave edges are blown into froth, and the sea is covered with patches of foam.
    		 37 feet
    12
    		 73+
    		 64+
    		 Hurricane
    		 Extreme destruction, devastation. The air is filled with foam and spray, and the sea is completely white, little visibility.
    		 45 feet

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