BEAUFORT WIND SCALE

BEAUFORT WIND SCALE

(After Chapman Piloting Seamanship & Small Boat Handling, 60th Edition)

Force Wind Speed (Kts) Description Effects at Sea Effects Near Land
0 under 1 Calm Sea like a mirror Calm
1 1-3 Light Air Ripples with appearance of scales; no foam crests Small sailboat just has steerage way
2 4-6 Light Breeze Small wavelets; crests of glassy appearance, not breaking Wind fills the sails of small boats which then travel at about 1-2 knots
3 7-10 Gentle Breeze Large wavelets; crests begin to break, scattered whitecaps Sailboats begin to heel and travel at about 3-4 knots
4 11-16 Moderate Breeze Small waves 0.5-1.25 meters high, becoming longer; numberous whitecaps Good working breeze, sailboats carry all sail with good heel
5 17-21 Fresh Breeze Moderate waves of 1.25-2.5 meters taking longer form; many whitecaps; some spray Sailboats shorten sail
6 22-27 Strong Breeze Larger waves 2.5-4 meters forming; whitecaps everywhere; more spray Sailboats have double reefed mainsails
7 28-33 Near Gale Sea heaps up, waves 4-6 meters; white foam from breaking waves begins to be blown in streaks Boats remain in harbor; those at sea heave-to
8 34-40 Gale Moderately high (4-6 meter) waves of greater lenght; edges of crests begin to break into spindrift; foam is blown in well-marked streaks All boats make for harbor, if near
9 41-47 Strong Gale High waves (6 meters); sea begins to roll; dense streaks of foam; spray may reduce visibility
10 48-55 Storm Very high waves (6-9 meters) with overhanging crests; sea takes a white appearance as foam is blown in very dense streaks; rolling is heavy and visibility is reduced
11 56-63 Violent Storm Exceptionally high (9-14 meters) waves; sea covered with white foam patches; visibility still more reduced
12 64-over Hurricane Air filled with foam; waves over 14 meters; sea completely white with driving spray; visibility greatly reduced