Each natural phenomenon, having different degrees of severity, is customary to evaluate in accordance with certain criteria. Especially if information about him must be transmitted quickly and accurately. For wind power, points in the Beaufort scale have become a single international benchmark.
Developed by the British rear admiral, a native of Ireland, Francis Beaufort (emphasis is placed on the second syllable) in 1806, a system improved in 1926 by adding information about the equivalence of wind power in points of its specific speed allows you to fully and accurately characterize this atmospheric process, while remaining relevant and to this day.
What is the wind?
Wind is the movement of air masses parallel to the surface of the planet (horizontally above it). This mechanism is caused by pressure differences. The direction of movement always comes from a higher area.
To describe the wind, it is customary to use the following characteristics:
- speed (measured in meters per second, kilometers per hour, knots and points);
- wind strength (in points and m.s. - meters per second, the ratio is approximately equal to 1: 2);
- direction (according to the cardinal points).
The first two parameters are closely related. They can be denoted by units of measurement of each other.
The direction of the wind is determined on the side of the world where the movement began (from the north - the north wind, etc.). Speed determines the baric gradient.
Baric gradient (otherwise - a barometric gradient) - a change in atmospheric pressure per unit distance along the normal to the surface of equal pressure (isobaric surface) in the direction of decreasing pressure. In meteorology, they usually use a horizontal barometric gradient, that is, its horizontal component (Great Soviet Encyclopedia).
The speed and strength of the wind cannot be divided. The large difference in the indicators between the zones of atmospheric pressure generates a strong and rapid movement of air masses above the surface of the earth.
Features of measuring winds
In order to correctly correlate the data of meteorological services with their real situation or to correctly measure, you need to know what standard conditions are used by professionals.
- Measurement of the strength and speed of the wind occurs at a ten-meter height on an open, flat surface.
- The name of the direction of the wind is given by the side of the world from where it blows.
Drivers of water transport, as well as lovers of spending time in nature, often purchase anemometers, which determine the speed, which is easy to correlate with the strength of the wind in points. There are waterproof models. For convenience, devices of various compactness are produced.
In the Beaufort system, a description of the height of the waves correlated with a certain wind strength in points is given for open sea space. It will be much smaller in shallow waters and coastal zones.
From personal to worldwide use
Sir Francis Beaufort not only had a high military rank in the Navy, but was also a successful practical scientist who held important posts, a hydrographist and cartographer, who greatly benefited the country and the world. His name is one of the seas in the Arctic Ocean, washing Canada and Alaska. Antarctic island named after Beaufort.
Francis Beaufort created a convenient system for assessing wind strength in points, available for a fairly accurate determination of the severity of the phenomenon "by eye" for his own use in 1805. The scale had a gradation from 0 to 12 points.
In 1838, the system of visual assessment of weather and wind strength in points began to be officially used by the British fleet. In 1874, it was adopted by the international synoptic community.
In the 20th century, several improvements were made to the Beaufort scale - the ratio of points and verbal description of the manifestation of the elements with wind speed (1926), and five more divisions were added - points of gradation of hurricane strength (USA, 1955).
Beaufort score criteria
In its modern form, the Beaufort scale has several characteristics that allow the complex to most accurately correlate a specific atmospheric phenomenon with its performance in points.
- Firstly, this is verbal information. A verbal description of the weather.
- Average speed in meters per second, kilometers per hour and knots.
- The impact of moving air masses on characteristic objects on land and sea is determined by typical manifestations.
Harmless wind
Safe wind is determined in the range from 0 to 4 points.
Points | Title | Wind speed (m / s) | Wind speed (km / h) | Wind speed (sea ulzy) | Description | Characteristic |
0 | Calm, complete calm (Calm) | 0-0.2 | less than 1 km / h | up to 1 node | Smoke movement - vertically up, tree leaves do not move | The surface of the sea is immovable, smooth |
1 | Silent wind (Light Air) | 0.3-1.5 | 1-5 | 1-3 | The smoke has a small angle, the vane is motionless | Light ripples without foam. Waves not higher than 10 centimeters |
2 | Light (Light Breeze) | 1.6-3.3 | 6-11 | 4-6 | Feelings of wind are felt by the skin of the face, there is movement and rustling of leaves, a slight movement of the weather vane | Short low waves (up to 30 centimeters) with a glass-like comb |
3 | Weak (Gentle Breeze) | 3.4-5.4 | 12-19 | 7-10 | Continuous movement of foliage and thin branches on trees, flapping flags | The waves remain short but more visible. The combs begin to tip over and turn into foam. Rare small “lamb” appear. The height of the waves reaches 90 centimeters, but on average does not exceed 60 |
4 | Moderate (Moderate Breeze) | 5.5-7.9 | 20-28 | 11-16 | The rise of dust, small debris from the ground begins | The waves become longer and rise up to one and a half meters. "Lamb" appear often |
A 5-point wind characterized as “fresh” or fresh breeze can be called borderline. Its speed ranges from 8 to 10.7 meters per second (29-38 km / h, or from 17 to 21 knots). Thin trees swing along with trunks. Waves rise to 2.5 (an average of two) meters. Sometimes splashes appear.
Trouble wind
With a wind power of 6 points, strong phenomena begin that can cause damage to health and property.
| Points | Title | Wind speed (m / s) | Wind speed (km / h) | Wind speed (sea ulzy) | Description | Characteristic |
6 | Strong (Strong Breeze) | 10.8-13.8 | 39-48 | 22-27 | Thick branches of trees sway violently, the roar of telegraph wires is heard | The formation of large waves, foam crests acquire a significant amount, splashes are likely. The average wave height is about three meters, the maximum reaches four |
7 | Strong (Moderate gale) | 13.9-17.1 | 50-61 | 28-33 | Trees swinging whole | Active movement of waves up to 5.5 meters high overlapping them on each other, foam scatter along the line of wind movement |
8 | Very Strong (Gale) | 17.2-20.7 | 62-74 | 34-40 | Tree branches break from the pressure of the wind, it is difficult to walk against its direction | Waves of considerable length and height: medium - about 5.5 meters, maximum - 7.5 m. Moderately high long waves. Spray take off. The foam lays in stripes, the vector coincides with the direction of the wind |
9 | Storm (Strong gale) | 20.8-24.4 | 75-88 | 41-47 | Wind damages buildings, begins to destroy roof tiles | Waves up to ten meters with an average height of up to seven. Strips of foam become wider. Tipping ridges fly apart. Reduced visibility |
Dangerous wind power
A wind of ten to twelve points is dangerous and is characterized as a violent storm and violent storm, as well as a hurricane.
The wind rips out trees along with the roots, damages buildings, destroys vegetation, destroys buildings. The waves make a deafening noise from 9 meters and above, long. At sea, they reach dangerous heights even for large vessels - from nine meters and above. Foam covers the water surface, visibility is zero or close to this indicator.
The speed of movement of air masses is from 24.5 meters per second (89 km / h) and reaches from 118 kilometers per hour with a wind force of 12 points. A severe storm and a hurricane (winds equal to 11 and 12 points) are very rare.
Extra Five Points to the Beaufort Classic Scale
Since hurricanes are also not identical in intensity and degree of damage, in 1955, the Weather Bureau of the United States of America adopted an addition to the standard Beaufort classification in the form of five units of the scale. Wind strength from 13 to 17 points inclusive - these are clarifying characteristics for destructive hurricane winds and related environmental phenomena.
How to protect yourself when the elements rage?
If the EMERCOM storm warning catches in an open area, it is better to follow the advice and reduce the risk of accidents.
First of all, you should pay attention to warnings every time - there is no guarantee that the atmospheric front will come to the area where you are, but you also cannot be sure that it will again bypass it. All items should be removed or securely secured, protect pets.
If a heavy wind catches in an unstable structure - a garden house or other lightweight constructions - it is better to close the windows on the air side and, if necessary, strengthen them with shutters or boards. With the leeward, on the contrary, slightly open and fix in this position. This eliminates the danger of an explosive effect from pressure differences.
In nature, you need to take a place away from tall trees, power lines. Tents will be safer in light forests.
It is important to remember that any strong wind can bring unwanted precipitation with you - in winter these are blizzards and snowstorms, in the summer dust and sand storms are possible. It should also be borne in mind that strong winds can occur in absolutely clear weather.