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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  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Admiral Francis Beaufort

Francis Beaufort was born in 1774 in County Meath, Ireland and began his nautical career at 13 as a cabin boy in the Navy. He realised that it was important whilst at sea to be aware of, and know about weather conditions, so started to keep a meteorological journal, which he continued to do until he died.

Beaufort invented the Beaufort Scale in 1806, and used it from then onwards, the Royal Navy then adopted his method in 1838, although over the next hundred years theBeaufort Scale was slightly adapted it is still based around Francis Beaufort's concept.

 

 

 

 

 

 

 

 

 

Wind Speed Fun Facts

A sneeze can travel as fast as 100 miles per hour. The fastest ever recorded was 103.6 mph. A cough, by the way, produces air travelling upwards of 60 mph.

Hurricane Andrew, which devastated Homestead, Florida City, and the surrounding area in 1992, was Florida's most devastating hurricane and the costliest natural disaster in American history at that time.

The hurricane of 1938 ripped through New York, New England, and Canada, packing wind gusts as high as 186 mph. The damage report included 700 people killed, 63,000 people homeless, an estimated 2 billion trees destroyed and 750,000 chickens killed.

Doldrums are equatorial belts of calm around the earth, centred slightly north of the equator between the two belts of trade winds. The doldrums are noted for calms, periods when the winds disappear, trapping sailing vessels for days or weeks. However, hurricanes originate in this region of low pressure and high humidity.