|Beaufort Number or Force
||Wind Speed and Description
||Probable Wave Height
||Still, calm air, smoke will rise vertically. Smooth like a
||Rising smoke drifts, wind vane is inactive. Small ripples
like fish scales.
||¼ - ½ foot
||Leaves rustle, can feel wind on your face, wind vanes
begin to move. Short, small pronounced wavelets with no crests.
||¼ - ½ foot
||Leaves and small twigs move, light weight flags extend.
Large wavelets, crests start to break, some whitecaps.
||Small branches move, raises dust, leaves and paper. Small
waves develop, becoming longer, whitecaps.
||Small trees sway. Moderate lengthening waves, with many
white caps and some spray.
||Large tree branches move, telephone wires begin to "whistle"Large
waves, extensive white caps, some spray.
||Large trees sway, becoming difficult to walk. Heaps of
waves, with some breakers whose foam is blown downwind in streaks.
||Twigs and small branches are broken from trees, walking is
difficult. Moderately large waves with blown foam.
||Slight damage occurs to buildings, shingles are blown off
of roofs. Rolling seas, dense foam, Blowing spray reduces visibility.
||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.
||Extensive widespread damage. Wave edges are blown into
froth, and the sea is covered with patches of foam.
||Extreme destruction, devastation. The air is filled with
foam and spray, and the sea is completely white, little visibility.