Contact Details
Magdalen Court School
Victoria Park Road
Exeter
EX2 4NU

Tel: 01392-49 49 19
Fax: 0870-7051-321

E-mail: Enquires@MagdalenCourtSchool.co.uk

For further contact details
please click here

 

Beaufort Wind Scale

  Developed in 1805 by Sir Francis Beaufort of England 


Force Wind
(Knots)
WMO
Classification
Appearance of Wind Effects
On the Water On Land
0 Less than 1 Calm Sea surface smooth and mirror-like Calm, smoke rises vertically
1 1-3 Light Air Scaly ripples, no foam crests Smoke drift indicates wind direction, still wind vanes
2 4-6 Light Breeze Small wavelets, crests glassy, no breaking Wind felt on face, leaves rustle, vanes begin to move
3 7-10 Gentle Breeze Large wavelets, crests begin to break, scattered whitecaps Leaves and small twigs constantly moving, light flags extended
4 11-16 Moderate Breeze Small waves 1-4 ft. becoming longer, numerous whitecaps Dust, leaves, and loose paper lifted, small tree branches move
5 17-21 Fresh Breeze Moderate waves 4-8 ft taking longer form, many whitecaps, some spray Small trees in leaf begin to sway
6 22-27 Strong Breeze Larger waves 8-13 ft, whitecaps common, more spray Larger tree branches moving, whistling in wires
7 28-33 Near Gale Sea heaps up, waves 13-20 ft, white foam streaks off breakers Whole trees moving, resistance felt walking against wind
8 34-40 Gale 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
9 41-47 Strong Gale High waves (20 ft), sea begins to roll, dense streaks of foam, spray may reduce visibility Slight structural damage occurs, slate blows off roofs
10 48-55 Storm 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"
11 56-63 Violent Storm Exceptionally high (30-45 ft) waves, foam patches cover sea, visibility more reduced  
12 64+ Hurricane Air filled with foam, waves over 45 ft, sea completely white with driving spray, visibility greatly reduced  

National Weather Service Chicago
Has a really nice Beaufort Wind Scale Chart with photos of sea, showing what it looks like at different wind scales.

 

Last Updated: Wed 20-Jan-2016 4:40 PM