Beaufort scale

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Force 12 at sea

The Beaufort scale is an empirical measure that relates wind speed tae observed condeetions at sea or on laund. Its full name is the Beaufort wind force scale.

Modern scale[eedit | eedit soorce]

Beaufort nummer Description Wind speed Waw hicht Sea condeetions Laund condeetions Sea state photo Associatit wairnin banner
0 Caum < 1 km/h 0 m Sea lik a mirror Calm. Smoke rises vertically. Beaufort scale 0.jpg
< 1 mph
< 1 knot 0 ft
< 0.3 m/s
1 Licht air 1–5 km/h 0–0.2 m Ripples wi the appearance o scales are formed, but wioot foam crests Smoke drift indicates wind direction. Leaves an wind vanes are stationary. Beaufort scale 1.jpg
1–3 mph
1–3 knots 0–1 ft
0.3–1.5 m/s
2 Licht breeze 6–11 km/h 0.2–0.5 m Smaw wawlets, still short but mair pronoonced; crests hae a glassy appearance an dinna break Wind felt on exposed skin. Leaves rustle. Wind vanes begin tae muive. Beaufort scale 2.jpg
4–7 mph
4–6 knots 1–2 ft
1.6–3.3 m/s
3 Gentle breeze 12–19 km/h 0.5–1 m Lairge wawlets. Crests begin tae break; scattered whitecaps Leaves an small twigs constantly muivin, licht flags extendit. Beaufort scale 3.jpg
8–12 mph
7–10 knots 2–3.5 ft
3.4–5.5 m/s
4 Moderate breeze 20–28 km/h 1–2 m Smaw waws wi breakin crests. Fairly frequent whitecaps. Dust an loose paper raised. Smaw branches begin tae muive. Beaufort scale 4.jpg
13–18 mph
11–16 knots 3.5–6 ft
5.5–7.9 m/s
5 Fresh breeze 29–38 km/h 2–3 m Moderate waws o some lenth. Mony whitecaps. Smaw amoonts o spray. Branches o a moderate size muive. Smaw trees in leaf begin tae sway. Beaufort scale 5.jpg
19–24 mph
17–21 knots 6–9 ft
8–10.7 m/s
6 Strang breeze 38–49 km/h 3–4 m Lang waws begin tae form. White foam crests are very frequent. Some airborne spray is present. Lairge branches in motion. Whistlin heard in owerheid wires. Umbrella uise acomes difficult. Empty plastic bins tip ower. Beaufort scale 6.jpg Gale pennant.svg
25–31 mph
22–27 knots 9–13 ft
10.8–13.8 m/s
7 Heich wind,
moderate gell,
near gell
50–61 km/h 4–5.5 m Sea heaps up. Some foam frae breakin waws is blawn intae streaks alang wind direction. Moderate amounts o airborne spray. Whole trees in motion. Effort needed tae walk against the wind. Beaufort scale 7.jpg Gale pennant.svg
32–38 mph
28–33 knots 13–19 ft
13.9–17.1 m/s
8 Gell,
fresh gell
62–74 km/h 5.5–7.5 m Moderately heich waws wi breakin crests formin spindrift. Well-merked streaks o foam are blawn alang wind direction. Considerable airborne spray. Some twigs broken frae trees. Caurs veer on road. Progress on fit is seriously impedit. Beaufort scale 8.jpg Gale pennant.svg
Gale pennant.svg
39–46 mph
34–40 knots 18–25 ft
17.2–20.7 m/s
9 Strang/severe gell 75–88 km/h 7–10 m Heich waws whase crests whiles row ower. Dense foam is blawn alang wind direction. Lairge amoonts o airborne spray mey begin tae reduce visibility. Some branches break off trees, an some smaw trees blaw ower. Construction/temporary signs an barricades blaw ower. Beaufort scale 9.jpg Gale pennant.svg
Gale pennant.svg
47-54 mph
41–47 knots 23–32 ft
20.8–24.4 m/s
10 Storm,[1]
whole gell
89–102 km/h 9–12.5 m Very heich waws wi owerhangin crests. Lairge patches o foam frae waw crests gie the sea a white appearance. Considerable tumblin o waws wi hivy impact. Lairge amoonts o airborne spray reduce veesibility. Trees are broken off or upruitit, structural damage likly. Beaufort scale 10.jpg Storm warning.svg
55–63 mph
48–55 knots 29–41 ft
24.5–28.4 m/s
11 Violent storm 103–117 km/h 11.5–16 m Exceptionally heich waws. Very lairge patches o foam, driven afore the wind, cover much o the sea surface. Very lairge amounts o airborne spray severely reduce veesibility. Widespread vegetation an structural damage likly. Beaufort scale 11.jpg Storm warning.svg
64–72 mph
56–63 knots 37–52 ft
28.5–32.6 m/s
12 Hurricane force [1] ≥ 118 km/h ≥ 14 m Huge waws. Sea is completely white wi foam an spray. Air is filled wi drivin spray, greatly reducin visibility. Severe widespread damage tae vegetation an structurs. Debris an unsecured objects are hurled aboot. Beaufort scale 12.jpg Storm warning.svg

Storm warning.svg
≥ 73 mph
≥ 64 knots ≥ 46 ft
≥ 32.7 m/s
References: Met Office,[2] Royal Meteorological Society,[3] Encyclopædia Britannica[4]

References[eedit | eedit soorce]

  1. 1.0 1.1 The names "storm" an "hurricane" on the Beaufort scale refer anly tae wind strenth, an dinna necessarily mean that ither severe wather (for instance, a thunnerstorm or tropical cyclone) is present. Tae avoid confusion, strang wind wairnins will eften speak of e.g. "hurricane-force winds".
  2. "Beaufort wind force scale". Met Office. Retrieved November 27, 2015. 
  3. "Beaufort Scale". Royal Meteorological Society. Retrieved November 27, 2015. 
  4. "Beaufort Scale". Encyclopædia Britannica. Retrieved November 27, 2015.