Determining Wind Speed By Sea State

Estimating Wind Speed and Sea State with Visual CluesBeaufort Wind Wave Wind Speed Visual Cluesnumber Description Height 0 Calm 0 knots 0 feet Sea is like a mirror Smoke rises vertically 1 Light Air 13 kts 12 Ripples with the appearance of scales are formed but without foam crests Smoke drifts from funnel Small wavelets still short but more pronounced crests have glassy 2 Light breeze 46 kts 12 ft max 1 appearance and do not break Wind felt on face Smoke rises at about 80 degrees Large wavelets crests begin to break Foam of glassy appearance Perhaps 3 Gentle Breeze 710 kts 2 ft max 3 scattered white horses white caps Wind extends light flag and pennants Smoke rises at about 70 deg Small waves becoming longer Fairly frequent white horses white caps 4 Moderate Breeze 1116 kts 3 ft max 5 Wind raises dust and loose paper on deck Smoke rises at about 50 deg No noticeable sound in the rigging Slack halyards curve and sway Heavy flag flaps limply Moderate waves taking more pronounced long form Many white horses white caps are formed chance of some spray 5 Fresh Breeze 1721kts 6 ft max 8 Wind felt strongly on face Smoke rises at about 30 deg Slack halyards whip while bending continuously to leeward Taut halyards maintain slightly bent position Low whistle in the rigging Heavy flag doesnt extended but flaps over entire length Large waves begin to form White foam crests are more extensive everywhere probably some spray 6 Strong Breeze 2227 kts 9 ft max 12 Wind stings face in temperatures below 35 deg F 2C Slight effort in maintaining balance against wind Smoke rises at about 15 deg Both slack and taut halyards whip slightly in bent position Low moaning rather than whistle in the rigging Heavy flag extends and flaps more vigorous Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of wind Necessary to lean slightly into the wind to maintain balance Smoke rises at about 5 to 10 deg Higher pitched moaning 7 Near Gale 2833 kts 13 ft max 19 and whistling heard from rigging Halyards still whip slightly Heavy flag extends fully and flaps only at the end Oilskins and loose clothing inflate and pull against the body Moderately high waves of greater length Edges of crests begin to break into the spindrift The foam is blown in wellmarked streaks along the direction of 8 Gale 3440 kts 18 ft the wind Head pushed back by the force of the wind if allowed to relax max 25 Oilskins and loose clothing inflate and pull strongly Halyards rigidly bent Loud whistle from rigging Heavy flag straight out and whipping High waves Dense streaks of foam along direction of wind Crests of waves 9 Strong Gale 4147 kts 23 ft max 32 begin to topple tumble and roll over Spray may affect visibility Very high waves with long overhanging crests The resulting foam in great patches is blown in dense streaks along the direction of the wind On the10 Storm 4855 kts 29 ft max 41 whole the sea takes on a whitish appearance Tumbling of the sea becomes heavy and shocklike Visibility affected Exceptionally high waves small and mediumsized ships might be for time lost to view behind the waves The sea is completely covered with long11 Violent Storm 5663 kts 37 ft max 52 white patches of foam lying along the direction of the wind Everywhere the edges of the wave crests are blown into froth Visibility greatly affected The air is filled with foam and spray The sea is completely white with driving12 Hurricane 64 kts 45 ft spray Visibility is seriously affected