Wind force determination scale. Storms, squalls, hurricanes, their characteristics, damaging factors
Scale for determining the speed, strength and name of wind (Beaufort scale)
Distinguish smoothed speed over a short period of time and instant, speed at a given time. Speed is measured with an anemometer using a Wild board.
The highest average annual wind speed (22 m/sec) was observed on the coast of Antarctica. The average daily speed there sometimes reaches 44 m/sec, and at some moments reaches 90 m/sec.
Wind speed has a daily cycle. It is close to the daily temperature variation. The maximum speed in the surface layer (100 m in summer, 50 m in winter) is observed at 13-14 hours, the minimum speed is at night. In higher layers of the atmosphere the diurnal variation in velocity is reversed. This is explained by changes in the intensity of vertical exchange in the atmosphere during the day. During the day, intense vertical exchange complicates the horizontal movement of air masses. At night there is no such obstacle and the Vm move in the direction of the pressure gradient.
The wind speed depends on the pressure difference and is directly proportional to it: the greater the pressure difference (horizontal baric gradient), the greater the wind speed. The average long-term wind speed at the earth's surface is 4-9 m/s, rarely more than 15 m/s. In storms and hurricanes (moderate latitudes) - up to 30 m/s, in gusts up to 60 m/s. In tropical hurricanes, wind speeds reach up to 65 m/s, and gusts can reach 120 m/s.
Instruments that measure wind speed are called anemometers. Most anemometers are built on the principle of a windmill. For example, the Fuss anemometer has four hemispheres (cups) at the top facing one direction (Fig. 75).
This system of hemispheres rotates about a vertical axis, and the number of revolutions is noted by a counter. The device is set to the wind, and when the “mill of hemispheres” acquires a more or less constant speed, the counter is turned on for a precisely defined time. Using a sign that indicates the number of revolutions for each wind speed, the speed is determined by the number of revolutions found. There are more complex instruments that have a device for automatically recording wind direction and speed. Simple instruments are also used, which can simultaneously determine the direction and strength of the wind. An example of such a device is the Wild weather vane, which is common at all meteorological stations.
The direction of the wind is determined by the side of the horizon from which the wind blows. Eight main directions (points of reference) are used to designate it: N, NW, W, SW, S, SE, E, NE. The direction depends on the pressure distribution and on the deflecting effect of the Earth's rotation.
Rose of Wind. Winds, like other phenomena in the life of the atmosphere, are subject to strong changes. Therefore, here too we have to find average values.
To determine the prevailing wind directions for a given period of time, proceed as follows. Eight main directions, or bearings, are drawn from any point, and the frequency of winds is plotted on a certain scale at each. The resulting image, known as wind roses, the prevailing winds are clearly visible (Fig. 76).
The strength of the wind depends on its speed and shows what dynamic pressure the air flow exerts on any surface. Wind force is measured in kilograms per square meter (kg/m2).
Wind structure. The wind cannot be imagined as a homogeneous air current, having the same direction and the same speed throughout its entire mass. Observations show that the wind blows gustyly, as if in separate shocks, sometimes subsides, then again acquires its previous speed. At the same time, the direction of the wind is also subject to changes. Observations made in higher layers of air show that gustsiness decreases with height. It has also been noted that at different times of the year and even at different hours of the day, wind gusts are not the same. The greatest gustiness is observed in spring. During the day, the greatest weakening of the wind occurs at night. Wind gustiness depends on the nature of the earth's surface: the more unevenness, the greater the gustiness and vice versa.
Causes of winds. The air remains at rest as long as the pressure in a given part of the atmosphere is distributed more or less evenly. But as soon as the pressure in any area increases or decreases, air will flow from the place of greater pressure towards less. The movement of air masses that has begun will continue until the pressure difference is equalized and equilibrium is established.
A stable equilibrium in the atmosphere is almost never observed, which is why winds are one of the most frequently recurring phenomena in nature.
There are many reasons that disturb the balance of the atmosphere. But one of the first reasons that creates a pressure difference is a temperature difference. Let's look at the simplest case.
Before us is the surface of the sea and the coastal part of the land. During the day, the land surface heats up faster than the sea surface. Due to this, the lower layer of air over land expands more than over the sea (Fig. 77, I). As a result, an air flow is immediately created at the top from a warmer region to a colder one (Fig. 77, II).
Due to the fact that part of the air from the warm region has flowed (at the top) towards the cold one, the pressure within the cold region will increase, and within the warm region it will decrease. As a result, an air current arises, now in the lower layer of the atmosphere, from a cold region to a warm one (in our case, from sea to land) (Fig. 77, III).
Such air currents usually arise on the sea coast or along the shores of large lakes and are called breezes. In the example we gave, it is a daytime breeze. At night the picture is completely opposite, because the land surface, cooling faster than the sea surface, becomes colder. As a result, in the upper layers of the atmosphere the air will flow towards land, and in the lower layers towards the sea (night breeze).
The rise of air from a warm area and the descent in a cold area unites the upper and lower flows and creates a closed circulation (Fig. 78). In these closed gyres, the vertical parts of the path are usually very small, while the horizontal parts, on the contrary, can reach enormous sizes.
Reasons for different wind speeds. It goes without saying that wind speed should depend on the pressure gradient (i.e., determined primarily by the difference in pressure per unit distance). If, apart from the force due to the gradient, no other forces acted on the mass of air, then the air would move uniformly and accelerated. However, this does not work, because there are many reasons that slow down the movement of air. This primarily includes friction.
There are two types of friction: 1) friction of the surface layer of air on the earth's surface and 2) friction that occurs inside the moving air itself.
The first is directly dependent on the nature of the surface. For example, the water surface and flat steppe create the least friction. Under these conditions, wind speed always increases significantly. An uneven surface creates greater obstacles to moving air, which leads to a decrease in wind speed. Urban buildings and forest plantations especially significantly reduce wind speed (Fig. 79).
Observations made in the forest showed that already at 50 m from the edge the wind speed decreases to 60-70% of the original speed, at 100 m up to 7%, in 200 m up to 2-3%.
The friction that occurs between adjacent layers of moving air masses is called internal friction. Internal friction causes the transfer of motion from one layer to another. The surface layer of air, as a result of friction with the earth's surface, has the slowest movement. The layer lying above, in contact with the moving lower layer, also slows down its movement, but to a much lesser extent. The next layer experiences even less impact, etc. As a result, the speed of air movement gradually increases with height.
Wind direction. If the main cause of wind is a difference in pressure, then the wind should blow from an area of higher pressure to an area of lower pressure in a direction perpendicular to the isobars. However, this does not happen. In reality (as established by observations) the wind blows mainly along the isobars and only slightly deviates towards low pressure. This occurs due to the deflecting effect of the Earth's rotation. We have already said at one time that any moving body, under the influence of the rotation of the Earth, deviates from its original path in the northern hemisphere to the right, and in the southern hemisphere to the left. They also said that the deflecting force in the direction from the equator to the poles increases. It is absolutely clear that the movement of air, which arises due to the pressure difference, immediately begins to experience the influence of this deflecting force. By itself, this power is small. But thanks to the continuity of its action, in the end the effect is very great. If there were no friction and other influences, then as a result of a continuously acting deflection, the wind could describe a closed curve close to a circle. In fact, due to the influence of various reasons, such a deviation does not occur, but nevertheless it is still very significant. It is enough to point out at least the trade winds, the direction of which, if the Earth is stationary, should coincide with the direction of the meridian. Meanwhile, their direction in the northern hemisphere is northeast, in the southern hemisphere - southeast, and in temperate latitudes, where the force of the deviation is even greater, the wind blowing from south to north takes on a west-southwest direction (in the northern hemisphere).
The main wind systems. The winds observed on the earth's surface are very diverse. Depending on the reasons that give rise to this diversity, we will divide them into three large groups. The first group includes winds, the causes of which depend mainly on local conditions, the second - winds caused by the general circulation of the atmosphere, and the third - the winds of cyclones and anticyclones. Let's begin our consideration with the simplest winds, the causes of which depend mainly on local conditions. Here we include breezes, various mountain, valley, steppe and desert winds, as well as monsoon winds, which depend not only on local causes, but also on the general circulation of the atmosphere.
Winds are extremely diverse in origin, character and meaning. Thus, in temperate latitudes, where westerly transport dominates, westerly winds (NW, W, SW) predominate. These areas occupy vast spaces - approximately from 30 to 60 ° in each hemisphere. In the polar regions, winds blow from the poles to low pressure zones at temperate latitudes. In these areas, northeast winds predominate in the Arctic and southeast winds in the Antarctic. At the same time, the southeastern winds of the Antarctic, in contrast to the Arctic, are more stable and have higher speeds.
Beaufort scale- a conventional scale for visually assessing the strength (speed) of the wind in points based on its effect on ground objects or on sea waves. It was developed by the English admiral F. Beaufort in 1806 and at first was used only by him. In 1874, the Standing Committee of the First Meteorological Congress adopted the Beaufort scale for use in international synoptic practice. In subsequent years, the scale was changed and refined. The Beaufort scale is widely used in maritime navigation.
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Wind strength at the earth's surface on the Beaufort scale |
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| Beaufort points | Verbal definition of wind force | Wind speed, m/sec | Wind action | |
| on the land | on the sea | |||
| 0 | Calm | 0-0,2 | Calm. Smoke rises vertically | Mirror smooth sea |
| 1 | Quiet | 0,3-1,5 | The direction of the wind is noticeable from the drift of the smoke, but not from the weather vane. | Ripples, no foam on the ridges |
| 2 | Easy | 1,6-3,3 | The movement of the wind is felt by the face, the leaves rustle, the weather vane is set in motion | Short waves, crests do not capsize and appear glassy |
| 3 | Weak | 3,4-5,4 | The leaves and thin branches of the trees sway all the time, the wind flutters the upper flags | Short, well defined waves. The ridges, overturning, form a glassy foam, occasionally small white lambs are formed |
| 4 | Moderate | 5,5-7,9 | The wind raises dust and pieces of paper and moves thin tree branches. | The waves are elongated, white caps are visible in many places |
| 5 | Fresh | 8,0-10,7 | Thin tree trunks sway, waves with crests appear on the water | Well developed in length, but not very large waves, white caps are visible everywhere (in some cases splashes are formed) |
| 6 | Strong | 10,8-13,8 | Thick tree branches sway, telegraph wires hum | Large waves begin to form. White foamy ridges occupy large areas (splashes are likely) |
| 7 | Strong | 13,9-17,1 | The tree trunks are swaying, it’s difficult to walk against the wind | The waves pile up, the crests break off, the foam lies in stripes in the wind |
| 8 | Very strong | 17,2-20,7 | The wind breaks tree branches, it is very difficult to walk against the wind | Moderately high long waves. Spray begins to fly up along the edges of the ridges. Strips of foam lie in rows in the direction of the wind |
| 9 | Storm | 20,8-24,4 | Minor damage; the wind tears off smoke hoods and tiles | High waves. The foam falls in wide dense stripes in the wind. The crests of the waves begin to capsize and crumble into spray, which impairs visibility |
| 10 | Heavy storm | 24,5-28,4 | Significant destruction of buildings, trees are uprooted. Rarely happens on land | Very high waves with long, downward-curving crests. The resulting foam is blown away by the wind in large flakes in the form of thick white stripes. The surface of the sea is white with foam. The strong roar of the waves is like blows. Visibility is poor |
| 11 | Fierce Storm | 28,5-32,6 | Large destruction over a large area. Very rarely observed on land | Exceptionally high waves. Small and medium-sized vessels are sometimes hidden from view. The sea is all covered with long white flakes of foam, located downwind. The edges of the waves are blown into foam everywhere. Visibility is poor |
| 12 | Hurricane | 32.7 or more | The air is filled with foam and spray. The sea is all covered with stripes of foam. Very poor visibility | |
The Beaufort scale is a conventional scale for visually assessing the strength (speed) of wind in points based on its effect on ground objects or on sea waves.
It was developed by the English admiral F. Beaufort in 1806 and at first was used only by him. In 1874, the Standing Committee of the First Meteorological Congress adopted the Beaufort scale for use in international synoptic practice.
In subsequent years, the scale was changed and refined. The Beaufort scale is widely used in maritime navigation.
| Beaufort points |
Verbal definition wind forces |
average speed wind, (m/s) |
average speed Wind,(km/h) |
average speed Wind, knots |
Actions of the wind |
Actions of the wind |
| 0 | Calm | 0 - 0.2 | < 1 | 0 - 1 | Calm. Smoke rises vertically. | Mirror smooth sea. |
| 1 | Easy | 0.3 - 1.5 | 1 - 5 | 1 - 3 | The direction of the wind is noticeable from the drift of the smoke, but not from the weather vane. | There are ripples and no foam on the ridges. |
| 2 | Quiet | 1.6 - 3.3 | 6 - 11 | 3.5 - 6.4 | The movement of the wind is felt by the face, the leaves rustle, the weather vane is set in motion. | Short waves, the crests do not capsize and appear glassy. |
| 3 | Weak | 3.4. - 5.4 | 12 - 19 | 6.6 - 10.1 | The leaves and thin branches of the trees sway all the time, the wind flutters the upper flags. | Short, well defined waves. The ridges, overturning, form a glassy foam, and occasionally small white lambs are formed. |
| 4 | Moderate | 5.5-7.9 | 20-28 | 10,3 - 14,4 | The wind raises dust and pieces of paper and sets thin tree branches in motion. | The waves are elongated, white caps are visible in many places. |
| 5 | Fresh | 8.0 - 10.7 | 29 - 38 | 14,6 - 19,0 | Thin tree trunks sway, waves with crests appear on the water. | The waves are well developed in length, but not very large; white caps are visible everywhere (in some cases, splashes form). |
| 6 | Strong | 10.8 - 13.8 | 39 - 49 | 19,2 - 24,1 | Thick tree branches sway and telegraph wires hum. | Large waves begin to form. White foamy ridges occupy large areas (splashes are likely). |
| 7 | Strong | 13.9 - 17.1 | 50 - 61 | 24,3 - 29,5 | The tree trunks are swaying, it is difficult to walk against the wind. | The waves pile up, the crests break off, the foam lies in stripes in the wind. |
| 8 | Very strong | 17.2 - 20.7 | 62 - 74 | 29,7 - 35,4 | The wind breaks the branches of the trees, it is very difficult to walk against the wind. | Moderately high long waves. Spray begins to fly up along the edges of the ridges. Strips of foam lie in rows in the direction of the wind. |
| 9 | Storm | 20.8 - 24.4 | 75 - 88 | 35,6 - 41,8 | Minor damage; the wind tears off smoke hoods and tiles. | High waves. The foam falls in wide dense stripes in the wind. The crests of the waves begin to capsize and crumble into spray, which impairs visibility. |
| 10 | Heavy storm | 24.5 - 28.4 | 89-102 | 42,0 - 48,8 | Significant destruction of buildings, trees are uprooted. Rarely happens on land. | Very high waves with long, downward-curving crests. The resulting foam is blown away by the wind in large flakes in the form of thick white stripes. The surface of the sea is white with foam. The strong roar of the waves is like blows. Visibility is poor. |
| 11 | Fierce Storm | 28.5 - 32.6 | 103-117 | 49,0 - 56,3 | Large destruction over a large area. Very rarely observed on land. | Exceptionally high waves. Small and medium-sized vessels are sometimes hidden from view. The sea is all covered with long white flakes of foam, located downwind. The edges of the waves are blown into foam everywhere. Visibility is poor. |
| 12 | Hurricane | > 32,6 | > 117 | >56 | Everything is very bad!!! | The air is filled with foam and spray. The sea is all covered with stripes of foam. Very poor visibility. |
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Beaufort scale
0 points - calm
Mirror-smooth sea, almost motionless. The waves practically do not run onto the shore. The water looks more like a quiet lake backwater than a sea coast. There may be haze over the surface of the water. The edge of the sea merges with the sky so that the border is not visible. Wind speed 0-0.2 km/h.
1 point - quiet
There are light ripples on the sea. The height of the waves reaches up to 0.1 meters. The sea can still merge with the sky. You can feel a light, almost imperceptible breeze.
2 points - easy
Small waves, no more than 0.3 meters high. The wind speed is 1.6-3.3 m/s, you can feel it with your face. With such wind, the weather vane begins to move.
3 points - weak
Wind speed 3.4-5.4 m/s. Slight disturbance on the water, whitecaps appear occasionally. The average wave height is up to 0.6 meters. The weak surf is clearly visible. The weather vane spins without frequent stops, leaves on the trees, flags, etc. sway.
4 points - moderate
Wind - 5.5 - 7.9 m/s - raises dust and small pieces of paper. The weather vane spins continuously, thin tree branches bend. The sea is rough and whitecaps are visible in many places. Wave height is up to 1.5 meters.
5 points - fresh
Almost the entire sea is covered with whitecaps. Wind speed 8 - 10.7 m/s, wave height 2 meters. Branches and thin tree trunks sway.
6 points - strong
The sea is covered with white ridges in many places. The height of the waves reaches 4 meters, the average height is 3 meters. Wind speed 10.8 - 13.8 m/s. Thin tree trunks and thick tree branches bend, telephone wires hum.
7 points - strong
The sea is covered with white foamy ridges, which from time to time are blown off the surface of the water by the wind. The height of the waves reaches 5.5 meters, the average height is 4.7 meters. Wind speed 13.9 - 17.1 m/s. The middle tree trunks sway and the branches bend.
8 points - very strong
Strong waves, foam on every crest. The height of the waves reaches 7.5 meters, the average height is 5.5 meters. Wind speed 17.2 - 20 m/s. Walking against the wind is difficult, talking is almost impossible. Thin branches of trees break.
9 points - storm
High waves on the sea, reaching 10 meters; average height 7 meters. Wind speed 20.8 - 24.4 m/s. Large trees bend, medium branches break. The wind tears off poorly reinforced roof coverings.
10 points - severe storm
The sea is white. The waves crash onto the shore or against the rocks with a roar. The maximum wave height is 12 meters, the average height is 9 meters. The wind, with a speed of 24.5 - 28.4 m/s, tears off roofs and causes significant damage to buildings.
11 points - severe storm
High waves reach 16 meters, with an average height of 11.5 meters. Wind speed 28.5 - 32.6 m/s. Accompanied by great destruction on land.
12 points - hurricane
Wind speed 32.6 m/s. Serious damage to permanent structures. The wave height is more than 16 meters.
Sea state scale
Unlike the generally accepted twelve-point wind rating system, there are several ratings of sea waves.
The generally accepted ones are British, American and Russian assessment systems.
All scales are based on a parameter that determines the average height of significant waves.
This parameter is called Significance Wave Height (SWH).
The American scale takes 30% of significant waves, the British 10%, and the Russian 3%.
The height of the wave is calculated from the crest (the top point of the wave) to the trough (the base of the trough).
Below is a description of the wave heights:
- 0 points - calm,
- 1 point - ripple (SWH< 0,1 м),
- 2 points - weak waves (SWH 0.1 - 0.5 m),
- 3 points - light waves (SWH 0.5 - 1.25 m),
- 4 points - moderate waves (SWH 1.25 - 2.5 m),
- 5 points - rough seas (SWH 2.5 - 4.0 m),
- 6 points - very rough seas (SWH 4.0 - 6.0 m),
- 7 points - strong waves (SWH 6.0 - 9.0 m),
- 8 points - very strong waves (SWH 9.0 - 14.0 m),
- 9 points - phenomenal waves (SWH > 14.0 m).
Since it determines not the strength of the storm, but the height of the wave.
A storm is defined by Beaufort.
For the WH parameter for all scales, it is the part of the waves that is taken (30%, 10%, 3%) because the magnitude of the waves is not the same.
At a certain time interval there are waves, for example, 9 meters, as well as 5, 4, etc.
Therefore, each scale had its own SWH value, where a certain percentage of the highest waves is taken.
There are no instruments to measure wave height.
Therefore, there is no exact definition of the score.
The definition is conditional.
On the seas, as a rule, the wave height reaches 5-6 meters in height and up to 80 meters in length.
Visual range scale
Visibility is the maximum distance at which objects can be detected during the day and navigation lights at night.
Visibility depends on weather conditions.
In metrology, the influence of weather conditions on visibility is determined by a conventional scale of points.
This scale is a way of indicating the transparency of the atmosphere.
There are day and night visibility ranges.
Below is the daily visual range scale:
Up to 1/4 cable
About 46 meters. Very poor visibility. Dense fog or snowstorm.
Up to 1 cable
About 185 meters. Bad visibility. Thick fog or wet snow.
2-3 cables
370 - 550 meters. Bad visibility. Fog, wet snow.
1/2 mile
About 1 km. Haze, thick haze, snow.
1/2 - 1 mile
1 - 1.85 km. Average visibility. Snow, heavy rain
1 - 2 miles
1.85 - 3.7 km. Haze, haze, rain.
2 - 5 miles
3.7 - 9.5 km. Light haze, haze, light rain.
5 - 11 miles
9.3 - 20 km. Good visibility. The horizon is visible.
11 - 27 miles
20 - 50 km. Very good visibility. The horizon is clearly visible.
27 miles
Over 50 km. Exceptional visibility. The horizon is clearly visible, the air is transparent.
Wind is a horizontal flow of air that differs in a number of specific characteristics: strength, direction and speed. It was to determine wind speed that the Irish admiral developed a special table at the beginning of the 19th century. The so-called Beaufort scale is still used today. What is the scale? How to use it correctly? And what does the Beaufort scale not allow you to determine?
What is wind?
The scientific definition of this concept is as follows: wind is an air flow that moves parallel to the earth's surface from an area of high to an area of low atmospheric pressure. This phenomenon is characteristic not only of our planet. Thus, the strongest winds in the solar system blow on Neptune and Saturn. And the earthly winds, in comparison with them, may seem like a light and very pleasant breeze.
The wind has always played an important role in human life. He inspired ancient writers to create mythical stories, legends and fairy tales. It was thanks to the wind that humans had the opportunity to travel significant distances by sea (with the help of sailboats) and by air (with the help of balloons). The wind is also involved in the “construction” of many earthly landscapes. Thus, it transports millions of grains of sand from place to place, thereby forming unique aeolian landforms: dunes, dunes and sand ridges.
At the same time, winds can not only create, but also destroy. Their gradient fluctuations can provoke a loss of control over the aircraft. Strong winds significantly expand the scale of forest fires, and on large bodies of water it creates huge waves that destroy houses and take lives. This is why it is so important to study and measure wind.
Basic wind parameters
It is customary to distinguish four main parameters of wind: strength, speed, direction and duration. All of them are measured using special devices. The strength and speed of the wind are determined using a so-called anemometer, and the direction - using a weather vane.
Based on the duration parameter, meteorologists distinguish squalls, breezes, storms, hurricanes, typhoons and other types of winds. The direction of the wind is determined by the side of the horizon from which it blows. For convenience, they are abbreviated with the following Latin letters:
- N (northern).
- S (south).
- W (western).
- E (east).
- C (calm).
Finally, wind speed is measured at a height of 10 meters using anemometers or special radars. Moreover, the duration of such measurements varies in different countries of the world. For example, at American meteorological stations the average speed of air flows is taken into account in 1 minute, in India - in 3 minutes, and in many European countries - in 10 minutes. The classic tool for presenting data on wind speed and strength is the so-called Beaufort scale. How and when did it appear?
Who is Francis Beaufort?
Francis Beaufort (1774-1857) - Irish sailor, naval admiral and cartographer. He was born in the small town of An Uavy in Ireland. After graduating from school, the 12-year-old boy continued his studies under the leadership of the famous Professor Usher. During this period, he first showed extraordinary ability to study “marine sciences”. As a teenager he entered the service of the East India Company and took an active part in surveying the Java Sea.
It should be noted that Francis Beaufort grew up to be a rather brave and courageous guy. Thus, during the shipwreck in 1789, the young man showed great dedication. Having lost all his food and personal belongings, he managed to save the team's valuable tools. In 1794, Beaufort took part in a naval battle against the French and heroically towed a ship that was hit by enemy fire.
Development of the wind scale
Francis Beaufort was extremely hardworking. Every day he woke up at five o'clock in the morning and immediately got to work. Beaufort was a significant authority among military men and sailors. However, he gained worldwide fame thanks to his unique development. While still a midshipman, the inquisitive young man kept a daily diary of weather observations. Later, all these observations helped him create a special wind scale. In 1838 it was officially approved by the British Admiralty.
One of the seas, an island in Antarctica, a river and a cape in northern Canada are named after the famous scientist and cartographer. Francis Beaufort also became famous for creating a polyalphabetic military cipher, which also received his name.
Beaufort scale and its features
The scale represents the earliest classification of winds according to their strength and speed. It was developed based on meteorological observations in open sea conditions. Initially, the classical Beaufort wind scale is twelve-point. Only in the middle of the twentieth century was it expanded to 17 levels so that hurricane-force winds could be distinguished.
Wind strength on the Beaufort scale is determined by two criteria:
- According to its effect on various ground objects and objects.
- According to the degree of roughness of the open sea.
It is important to note that the Beaufort scale does not allow you to determine the duration and direction of air flows. It contains a detailed classification of winds according to their strength and speed.
Beaufort scale: table for sushi
Below is a table detailing the effects of wind on ground objects and objects. The scale, developed by the Irish scientist F. Beaufort, consists of twelve levels (points).
Wind power (in points) | Wind speed | The effect of wind on objects |
| 0 | 0-0,2 | Complete calm. Smoke rises vertically |
| 1 | 0,3-1,5 | The smoke deviates slightly to the side, but the weather vanes remain motionless |
| 2 | 1,6-3,3 | The leaves on the trees begin to rustle, the wind is felt on the skin of the face |
| 3 | 3,4-5,4 | Flags flutter, leaves and small branches sway on the trees |
| 4 | 5,5-7,9 | The wind lifts dust and small debris from the ground |
| 5 | 8,0-10,7 | You can “feel” the wind with your hands. Thin trunks of small trees sway. |
| 6 | 10,8-13,8 | Large branches sway, wires hum |
| 7 | 13,9-17,1 | Tree trunks sway |
| 8 | 17,2-20,7 | Tree branches break. It becomes very difficult to go against the wind |
| 9 | 20,8-24,4 | Wind destroys awnings and roofs of buildings |
| 10 | 24,5-28,4 | Significant damage, wind can tear trees out of the ground |
| 11 | 28,5-32,6 | Large destruction over large areas |
| 12 | more than 32.6 | Huge damage to houses and buildings. The wind destroys vegetation |
Beaufort Table of Sea State
In oceanography there is such a thing as the state of the sea. It includes the height, frequency and strength of sea waves. Below is the Beaufort scale (table), which will help determine the strength and speed of the wind based on these signs.
Wind power (in points) | Wind speed | Effect of wind on the sea |
| 0 | 0-1 | The surface of the water mirror is perfectly flat and smooth |
| 1 | 1-3 | Small disturbances and ripples appear on the surface of the water |
| 2 | 4-6 | Short waves up to 30 cm in height appear |
| 3 | 7-10 | The waves are short, but clearly defined, with foam and “waddles” |
| 4 | 11-16 | Elongated waves up to 1.5 m in height appear |
| 5 | 17-21 | The waves are long with widespread “lambs” |
| 6 | 22-27 | Large waves with splashes and foamy crests form |
| 7 | 28-33 | Large waves up to 5 m high, foam falls in stripes |
| 8 | 34-40 | High and long waves with powerful spray (up to 7.5 m) |
| 9 | 41-47 | High (up to ten meters) waves are formed, the crests of which overturn and scatter with splashes |
| 10 | 48-55 | Very high waves that capsize with a strong roar. The entire surface of the sea is covered with white foam |
| 11 | 56-63 | The entire water surface is covered with long whitish flakes of foam. Visibility is significantly limited |
| 12 | over 64 | Hurricane. Visibility of objects is very poor. The air is oversaturated with spray and foam |
Thus, thanks to the Beaufort scale, people can observe the wind and estimate its strength. This makes it possible to make the most accurate weather forecasts.
