Beaufort Wind Scale
Developed in 1805 by Sir Francis Beaufort of
England
Sea surface smooth and mirror-like
Calm, smoke rises vertically
Scaly ripples, no foam crests
Smoke drift indicates wind
direction, still wind vanes
Small wavelets, crests glassy, no
breaking
Wind felt on face, leaves rustle,
vanes begin to move
Large wavelets, crests begin to break,
scattered whitecaps
Leaves and small twigs constantly
moving, light flags extended
Small waves 1-4 ft. becoming longer,
numerous whitecaps
Dust, leaves, and loose paper
lifted, small tree branches move
Moderate waves 4-8 ft taking longer form,
many whitecaps, some spray
Small trees in leaf begin to sway
Larger waves 8-13 ft, whitecaps common,
more spray
Larger tree branches moving,
whistling in wires
Sea heaps up, waves 13-20 ft, white foam
streaks off breakers
Whole trees moving, resistance
felt walking against wind
Moderately high (13-20 ft) waves of
greater length, edges of crests begin to
break into spindrift, foam blown in streaks
Whole trees in motion, resistance
felt walking against wind
High waves (20 ft), sea begins to roll,
dense streaks of foam, spray may reduce
visibility
Slight structural damage occurs,
slate blows off roofs
Very high waves (20-30 ft) with
overhanging crests, sea white with
densely blown foam, heavy rolling,
lowered visibility
Seldom experienced on land,
trees broken or uprooted,
"considerable structural damage"
Exceptionally high (30-45 ft) waves, foam
patches cover sea, visibility more reduced
Air filled with foam, waves over 45 ft, sea
completely white with driving spray,
visibility greatly reduced