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Beaufort wind scale – for nature journal keepers

 

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One of the first scales to estimate wind speeds and the effects was created by Britain’s Admiral Sir Francis Beaufort (1774-1857). He developed the scale in 1805 to help sailors estimate the winds via visual observations. The scale starts with 0 and goes to a force of 12.

The Beaufort scale is still used today to estimate wind strengths.
Naturalists can use it for the same purposes. While taking notes for your journal, notice how strong the wind is and how it affects trees, smoke, leaves, etc. You can even sketch what is happening.

Then when you write in your journal, you can record the suspected speed

Beaufort Wind Scale

Developed in 1805 by Sir Francis Beaufort of England


Force Wind
(Knots)
  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  

Beaufort WInd Scale courtesy of Storm Prediction Center of NOAA National Weather Center at http://www.spc.noaa.gov/faq/tornado/beaufort.html accessed 31 October 2011.


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