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BEAUFORT WIND SCALE

Bftm/sec
km/h
Knots Wind
Wave
Height in m
W M O
Description
Effects observed on sea
00,0-0,20-10-1 CalmSea like mirror.
10,3-1,51-51-30,1Light
air
Ripples with appearance of scales; no foam crests.
21,6-3,36-114-60,2-0,5Light
breeze
Small wavelets; crests of glassy appearance, not
breaking.
33,4-5,412-197-100,5-1,0Gentle
breeze
Large wavelets; crests begin to break; scattered
whitecaps.
45,5-7,920-2811-161,0-2,0Moderate
breeze
Small waves, becoming longer; numerous whitecaps.
58,0-10,729-3817-212,0-3,0Fresh
breeze
Moderate waves, taking longer form; many white
caps; some spray.
610,8-13,839-4922-273,0-4,0Strong
breeze
Larger waves forming whitecaps everywhere;
more spray.
713,9-17,150-6128-334,0-5,5Near
Gale
Sea heaps up; white foam from breaking waves
begin to be blown in streaks.
817,2-20,762-7434-405,5-7,5GaleModerately high waves of greater length; edges of crests begin
to break into spindrift; foam is blown in well-marked streaks.
920,8-24,475-8841-477,0-10,0Strong
gale
High waves; sea begins to roll; dense streaks of
foam; spray may reduce visibility.
1024,5-28,489-10248-559,0-12,5StormVery high waves with overhanging crests; sea takes
white appearance as foam is blown in very dense
streaks; rolling is heavy and visibility reduced.
1128,4-32,6103-11756-6311,5-16,0Violent
storm
Exceptionally high waves; sea covered with foam
patches; visibility still more reduced.
1232,7- 118-13364-7114,0+ HurricaneAir filled with foam; sea completely white with driving
spray; visibility greatly reduced.