- Beaufort scale of wind (nautical)
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▪ TableThe Beaufort scale of wind (nautical)Beaufort number name of wind wind speed description of sea surfaceknots kph0 calm <1 <1 sea like a mirror1 light air 1–3 1–5 ripples with appearance of scales are formed, without foam crests2 light breeze 4–6 6–11 small wavelets still short but more pronounced; crests have a glassy appearance but do not break3 gentle breeze 7–10 12–19 large wavelets; crests begin to break; foam of glassy appearance; perhaps scattered white horses4 moderate breeze 11–16 20–28 small waves becoming longer; fairly frequent white horses5 fresh breeze 17–21 29–38 moderate waves taking a more pronounced long form; many white horses are formed; chance of some spray6 strong breeze 22–27 39–49 large waves begin to form; the white foam crests are more extensive everywhere; probably some spray7 moderate gale (or near gale) 28–33 50–61 sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind; spindrift begins to be seen8 fresh gale (or gale) 34–40 62–74 moderately high waves of greater length; edges of crests break into spindrift; foam is blown in well-marked streaks along the direction of the wind9 strong gale 41–47 75–88 high waves; dense streaks of foam along the direction of the wind; sea begins to roll; spray affects visibility10 whole gale (or storm) 48–55 89–102 very high waves with long overhanging crests; resulting foam in great patches is blown in dense white streaks along the direction of the wind; on the whole the surface of the sea takes on a white appearance; rolling of the sea becomes heavy; visibility affected11 storm (or violent storm) 56–63 103–114 exceptionally high waves; small- and medium-sized ships might be for a long time lost to view behind the waves; sea is covered with long white patches of foam; everywhere the edges of the wave crests are blown into foam; visibility affected12–17 hurricane 64 and above 117 and above the air is filled with foam and spray; sea is completely white with driving spray; visibility very seriously affectedBeaufort number sea disturbance number average waveheightft m0 0 0 01 0 0 02 1 0–1 0–0.33 2 1–2 0.3–0.64 3 2–4 0.6–1.25 4 4–8 1.2–2.46 5 8–13 2.4–47 6 13–20 4–68 6 13–20 4–69 6 13–20 4–610 7 20–30 6–911 8 30–45 9–1412–17 9 over 45 over 14See as table:
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Universalium. 2010.