What clouds when it snows. Clouds - Types and forms of clouds

Clouds and determining the weather on them. From the shape of the clouds floating across the sky, one can guess with a reasonable degree of certainty what kind of weather will prevail during the day.

There are the following types of clouds.

Cirrus

Thin, light, haze-like white clouds, transparent to the sun. Variable in shape, more often they look like stripes, arcs or veins collected in bundles. At night, these clouds can scatter starlight. Mostly indicate a change in the weather. In combination with low cumulus and subsequent cirrostratus, they can herald the approach of a cyclone with rain.

cirrocumulus

They are located lower than pinnate. In the sky they are seen as ordered clusters of ragged small clubs or stripes, they have a spotted or pockmarked texture. At night, dim stars can outshine. Mostly associated with dry weather. However, if they thicken, turn gray and sink lower, you have to wait for rain.

Cirrostratus

Milky white thin veil of clouds.

May mix with cirrus and form parallel streaks on the palate. The sun or moon, shining through these clouds, acquire the shade of a halo. Expect weather changes. As in the case of cirrocumulus, if they sink and thicken, then rain can be expected during the day.

Altocumulus

Small flattened, rounded clusters, gray on the underside. They gather in loose, unorganized formations, between which the blue sky often peeps. Sometimes they look like rushing groups of clouds, rolling like waves. They can be thick enough to outshine the sun. At dawn and at sunset they create colorful patterns in the sky. If the clouds thicken and drop, short thunderstorms can be expected. If the altocumulus clouds are located higher, taking on the shape of towers, the thunderstorm can be even more severe.

Altostratus

A veiny and denser variant of cirrostratus clouds.

They scatter the light of stars and, when especially dense, can blur the disk of the sun or moon. If they descend, thicken and darken, or if low, gray, ragged clouds form below them, heavy and prolonged rain or snow is likely to begin in a few hours.

layered

Very low clouds, similar to fog, but raised above the ground by 150-600 m. Form a continuous layer. Usually they portend rainy weather, especially in combination with strong winds.

Strato-rainy

Homogeneous, dark gray layer of clouds covering sunlight. They are usually part of the main area of ​​low pressure. Usually bring prolonged, steady rain or snow.

Stratocumulus

Soft, rounded white clouds collected in ordered layers, lines, waves or elongated puffs. Often gray underneath. Stratocumulus clouds usually dissipate at night, leaving fine weather behind.

Cumulus

Classic white, "downy" clouds with a curled surface accentuated by shadows and a domed top. May be part of an anticyclone that brings clear weather. But if it starts to get dark, then this may portend strong wind and rain.

Cumulonimbus

Cumulus clouds that look like mountains of a dark, menacing color and with a flat base. Foreshadow heavy, heavy rains, and thunderstorm conditions are possible.

The concept of "cloudiness" refers to the number of clouds observed in one place. Clouds, in turn, are called atmospheric phenomena formed by a suspension of water vapor. The classification of clouds includes many of their types, divided by size, shape, nature of formation and altitude.

In everyday life, special terms are used to measure cloudiness. Expanded scales for measuring this indicator are used in meteorology, maritime affairs and aviation.

Meteorologists use a ten-point cloud scale, which is sometimes expressed as a percentage of coverage of the observable sky (1 point - 10% coverage). In addition, the height of cloud formation is divided into upper and lower tiers. The same system is used in maritime affairs. Aeronautical meteorologists use a system of eight octants (parts of the visible sky) with a more detailed indication of the height of the clouds.

A special device is used to determine the lower boundary of the clouds. But only aviation weather stations are in dire need of it. In other cases, it is visual assessment height.

Cloud types

Cloudiness plays an important role in the formation weather conditions. Cloud cover prevents the Earth's surface from heating and prolongs the process of its cooling. Cloud cover significantly reduces daily temperature fluctuations. Depending on the amount of clouds at a certain time, several types of cloudiness are distinguished:

1. "Clear or partly cloudy" corresponds to cloudiness of 3 points in the lower (up to 2 km) and middle tiers (2 - 6 km) or any amount of clouds in the upper (above 6 km).
2. "Changing or variable" - 1-3/4-7 points in the lower or middle tier.
3. "With clearings" - up to 7 points of total cloudiness of the lower and middle tiers.
4. "Cloudy, cloudy" - 8-10 points in the lower tier or not translucent clouds on average, as well as with precipitation in the form of rain or snow.

Types of clouds

The world classification of clouds distinguishes many types, each of which has its own Latin name. It takes into account the shape, origin, height of education and a number of other factors. The classification is based on several types of clouds:

• Cirrus clouds are thin filaments of white. They are located at an altitude of 3 to 18 km, depending on the latitude. They consist of falling ice crystals, to which they owe their appearance. Among the cirrus at a height of over 7 km, clouds are divided into cirrocumulus, altostratus, which have a low density. Below, at an altitude of about 5 km, there are altocumulus clouds.
• Cumulus clouds are dense formations of white color and a considerable height (sometimes more than 5 km). They are located most often in the lower tier with vertical development in the middle. Cumulus clouds at the upper boundary of the middle tier are called altocumulus.
• Cumulonimbus, shower and thunderclouds, as a rule, are located low above the Earth's surface 500-2000 meters, are characterized by precipitation precipitation in the form of rain, snow.
• Stratus clouds are a layer of low-density suspended matter. They let in the light of the sun and moon and are at an altitude of between 30 and 400 meters.

Cirrus, cumulus and stratus types, mixing, form other types: cirrocumulus, stratocumulus, cirrostratus. In addition to the main types of clouds, there are other, less common ones: silvery and mother-of-pearl, lenticular and vymeform. And clouds formed by fires or volcanoes are called pyrocumulative.

Scientists, naturalists and dreamers love to study clouds, and just watch them. At the sight of this or that celestial phenomenon, there is a desire to call it “big, heavy or rainy”, but it would be much more interesting (and more useful) to use scientific terminology for a more specific description.

For the first time, air halos (nimbus - a cloud in Latin) began to be classified by the English scientist Luke Howard, and the main criteria he used were the height of the tier, the shape and, in fact, the weather that created them.

The types of clouds are very diverse and are an interesting "collectible" and just to observe. Knowing about the celestial changes can be a great topic of conversation at a social dinner or a simple party.

Among other things, all the nuances regarding weather changes are essential for people involved in extreme sports such as boating or rock climbing. Types of clouds, their reading and analysis will help to avoid serious danger and learn about changes climatic conditions without additional metrological instruments.

• The height of the nimbus will tell you about the approaching storm.
• The form is about the stability of the atmosphere.
• Together, these factors will warn of critical changes in the weather (hail, snow or rain).

Despite the enormous variety and types of clouds, it is not so difficult to classify them, even according to appearance.

Spindrift clouds

In their appearance, they resemble fragile threads or shreds. The shape of cirrus clouds is similar to elongated ridges. It is one of the highest air connections in the troposphere from about 5 to 20 km above sea level depending on latitude.

Cirrus anomalies are remarkable in that they can stretch for several hundred kilometers. Visibility inside the cloud is very low and ranges from 200-300 meters. This is due to the fact that the nimbus consists of large ice crystals that fall rapidly.

because of gusty wind we observe not clear vertical stripes, but bizarrely curved threads of cirrus clouds.

Such changes indicate an approaching heavy rain or anticyclone in about a day.

cirrocumulus clouds

Like the previous species, cirrocumulus anomalies are located in the upper layers of the troposphere. They never give precipitation, but it can be clearly said that these types of clouds are harbingers of thunderstorms and heavy rainfall, and sometimes even a storm.

These nimbus are often called "lambs" for their bizarre shape in the form of groups of balls and circles. The height of the lower boundary of the clouds is slightly lower than simple cirrus and varies between 5-9 km with a vertical extension of about a kilometer. Visibility, unlike the previous type, is much better - from 5 to 10 kilometers.

An interesting feature of cirrocumulus species is iridescence, when the edges are painted in an iridescent color, which looks very impressive and beautiful.

Cirrostratus clouds

This type of nimbus is composed almost entirely of ice crystals and is quite easy to recognize. It looks like a uniform film covering the sky. It appears after the above types of clouds have “gone”. In winter, their length can vary up to 6 km, and in summer - from 2 to 4 km.

Visibility within the anomaly itself is extremely low: from about 30 to 150 meters. As in the case of the previous species, cirro-stratified flows promise an early change in the weather in the form of rains and thunderstorms.

What types of clouds precede rain? All feathery nimbus always move ahead of warm air masses, where there is very high humidity, which is the source of rain with showers. Therefore, we can say that all pinnate compounds are harbingers of bad weather.

Even though anomalies absorb sunlight and moonlight, sometimes very colorful phenomena (halos) can occur and rare types of clouds appear in the form of glowing and iridescent rings around the light of the moon or sun.

Altostratus clouds

In their appearance, they resemble a gloomy gray veil, through which only occasionally sunlight peeps through. High-layered compounds are located at an altitude of no more than 5 km above sea level and have a vertical length of up to 4 km.

Visibility in such a cloud is very small - 20-30 meters. They consist of ice crystals and supercooled water. These anomalies can be showered with light rain or snow, but in the summer the rain just doesn't reach the ground, so we mistakenly think they aren't rainy.

Altocumulus clouds

These connections can be the beginning of the soonest downpours. In their shape, they resemble small balls that gather in separate groups. The color scheme is very diverse: from white to dark blue. Very often you can see bizarre shapes: a cloud in the form of a heart, an animal, a flower and other interesting things.

The length of the high cumulus clouds small and rarely reaches a kilometer. Visibility, as well as in layered compounds, is small - 50-70 meters. They are located in the middle layers of the stratosphere and are 4-5 km away from the earth. In addition to rain fronts, they can bring cold snap with them.

Nimbostratus clouds

These are the views storm clouds dark gray color with a very "gloomy" character. They are a continuous cloudy veil, to which neither end nor edge is visible, with constantly pouring rain. This can go on for a very long time.

They are much darker than all other layered compounds and are located in the lower part of the stratosphere, so they hover almost above the ground (100-300 meters). Their thickness reaches several kilometers and the entire process of the passage of the front is accompanied by cold winds and low temperatures.

Cumulonimbus clouds

These are the most powerful nimbus that nature has given us. They can reach 14 km wide. The appearance of a cumulonimbus cloud is a thunderstorm, downpour, hail and squally wind. It is these anomalies that are called "clouds".

Sometimes they can line up in a whole series of squall fronts. The composition of cumulonimbus compounds can vary and depend on altitude. The bottom layer consists mainly of water droplets, while the top layer consists of ice crystals. This type of halo develops from the rain-stratified counterparts and their appearance cannot bode well.

The types of precipitation falling from the clouds can be very diverse: showers, snow, cereals, ice and needles, so it is better to wait out the bad weather under a roof or in any other shelter.

Fog

Fog also applies to low-lying compounds. It is thick and wet, and when you pass through a foggy cloud, you can feel its heaviness. Fog may appear in places of large water accumulation with light wind.

Very often it occurs on the surface of lakes and rivers, but if the wind rises, the fog dissipates very quickly without a trace.

Sometimes they cover the firmament in the form of a continuous veil, sometimes they appear in the form of isolated cloud masses, sometimes very powerfully developing in height, sometimes they have a relatively delicate structure, sometimes in the form of stripes or feathers of a fibrous structure, sometimes in the form of white small lambs, or scales, etc. The density of clouds largely depends on their height. The thickest and most powerful clouds usually float at a low altitude - below two kilometers. The higher the clouds float, the thinner and more transparent their structure becomes. All the clouds that we observe in the sky usually float in a layer from the surface to a height of 10-12 kilometers.

Our idea of ​​the weather is usually closely connected with the picture of the firmament, that is, with the forms and number of clouds observed in the sky.

Lower clouds

Fog

When the process of condensation of water vapor occurs in the lowest layers, the resulting cloud is located near the surface of the earth. It directly surrounds us and appears to us in the form of fog. In general, any cloud, if you are inside it, for example, on a mountain or when flying in an airplane, appears to the observer in the form of fog.

stratus clouds

Everyone knows the picture of clouds in gloomy gray weather, when the sky is covered with a continuous, completely uniform gray cloud cover, relatively low above the ground. It gives the impression of a raised fog. usually does not shine through this veil at all. Sometimes a light drizzle falls out of it in the form of fine water dust, while in winter sometimes the smallest rare snowflakes. These are the so-called stratus clouds (the international name is Stratus or abbreviated as St). Essentially, these clouds represent fog raised above the surface of the earth. They usually swim not high - sometimes at a height of a hundred or several hundred meters, usually not more than a kilometer.

In some cases, stratus clouds are torn into separate pieces with ragged edges. Then they are called stratus clouds (the international name is Fracto-Stratus or FrSt for short).

Nimbostratus clouds

Consider another picture of the sky. Bad weather. It's raining, but not one that breaks out quickly in the form of a downpour, and quickly passes, but rain (snow in winter), which, as they say, “charged for a long time” and over a large area (it is called a heavy rain). It may happen that there is no rain yet, but the very sight of the clouds makes one expect it soon. The clouds have the appearance of a low dark gray layer, almost uniform, so that only in some places this layer seems darker, in other places it is a little lighter. These typical inclement weather clouds are called nimbostratus or colloquially rain clouds (the international name is Nimbo-Stratus or NbSt for short).

Stratocumulus clouds

Stratocumulus clouds (international name Strato-Cumulus, abbr. StCu) should not be confused with the latter form of clouds, which appear as stretching dark cloud banks or spherical masses that give the sky a wavy appearance. Usually the cover of stratocumulus clouds is not continuous, but with gaps between individual shafts. These clouds are usually not accompanied by precipitation. They are most often found in winter time year, although they occur in the summer. In their form, they are, as it were, transitional from the stratus clouds described above to cumulus clouds, on which we will dwell.

Cumulus clouds

Let us now consider the form of clouds, which is usual for a good summer day. In the morning the sky is completely clear; but at about 8-10 o'clock light, white clouds begin to appear in the sky in some places. They grow rapidly both to the sides and, mainly, upwards. Their base is almost horizontal, while the tops have a dome-like appearance with separate, usually sharply defined bulges at the top. Illuminated by the sun, they appear to the observer of dazzling whiteness. If they are between the observer and the sun, they appear dark in the middle part.

These clouds grow during the day, but by the evening they usually begin to melt and gradually disappear. They are called cumulus (international name Cumulus, abbreviated Cu).

Thunderclouds

Sometimes clouds, which initially look like cumulus clouds, grow so intensely that they reach enormous sizes (often up to several kilometers), take the form of mountains or huge towers. The very top of the cloud often begins to take on a fibrous structure instead of the shape of bulges, and sometimes it looks like an anvil. Such clouds usually bring with them thunderstorms, downpours and hail, and in winter heavy snowfalls. They are called cumulonimbus clouds (international name Cumulo-Nimbus, abbreviated CuNb); when they are accompanied by thunderstorms, they are colloquially referred to as thunderstorms.

The five forms of clouds we have considered - stratus, nimbostratus, stratocumulus, cumulus and cumulonimbus are called "lower clouds". They float relatively low above the ground, so that their base is no higher than 2000 meters. For stratus clouds, the limiting level of the lower base is approximately two times less (usually they float no higher than 1000 meters). The clouds of the lower tier differ from other forms of clouds (middle and upper tiers) described below in their density and power, visibly obscuring the sun. In addition, floating at a relatively low altitude, they often create a well-known difficulty in flying. Flight in cumulonimbus clouds is further hampered by the fact that these clouds are often accompanied by whirlwinds and generally restless air movements.

Middle clouds

Let us now turn to the consideration of higher clouds, to the so-called "middle tier" clouds.

Altostratus clouds

A continuous cloud cover of the sky in the form of a grayish or bluish veil can also be located much higher than 1000 meters, that is, above the limit level at which ordinary stratus clouds float. This veil is usually so transparent that it makes it possible to distinguish the sun or moon as a more or less blurred spot. Such cloud cover is called altostratus clouds (international name Alto-Stratus, abbreviated as AlSt). Altostratus clouds, becoming denser, can gradually turn into nimbostratus clouds, which have more dark color completely covering the sun or moon. Overcast rain or snow sometimes falls from the layer of altostratus clouds.

Altocumulus clouds

These clouds have an international name - Aito-Cumuius, abbreviated as A-Cu. In appearance, they correspond to the cumulus clouds of the lower tier, although they differ from them in a much lower power, more delicate structure, and swim much higher. To the observer, altocumulus clouds appear as white caps, sometimes as small flakes of snow, or small rounded flakes of cotton wool, often approaching a spherical shape, with fairly distinct edges, or as flakes. Their thickness is so insignificant that they almost do not obscure the sun, due to which they appear uniformly white in the sky without shadows. These lambs, flakes or scales are usually arranged in connected groups or rows on the palate. Sometimes they appear as parallel bands or waves, which seem (due to "perspective") to converge at the horizon. Altocumulus clouds also belong to the clouds of the so-called "middle" tier. They usually swim at an altitude between 2000 and 6000 meters.

Upper clouds

To the highest cloud forms or clouds upper tier There are three forms: cirrocumulus, cirrostratus and cirrus.

cirrocumulus clouds

These clouds have the international name Cirro-Cumulus, abbreviated as CiCu. In transitional forms, they sometimes resemble in miniature high cumulus clouds, with which they can be confused. To the observer, cirrocumulus clouds appear as very small white flakes or miniature snowballs arranged in regular groups or rows, or as ripples in the sand. They sometimes form from the cirrostratus or cirrus clouds described below, and have a fibrous structure. They are of such a delicate structure that on their lower side they do not give a completely shadow.

Cirrostratus clouds

Similar to stratus clouds in the lower tier and high stratus in the middle, in the upper tier there is also a cloud form in the form of a continuous homogeneous veil, the so-called cirrostratus clouds (international name Cirro-Stratus or abbreviated CiSt). These clouds cover the sky with a solid whitish veil, completely washed out and giving the sky a whitish tint. Through this veil the sun can be seen so clearly that the edges of their discs are perfectly distinct and not blurred. A characteristic feature of cirrostratus clouds is the appearance of circles in the sky near the sun or moon.

Spindrift clouds

Sometimes very delicate individual clouds of a fibrous or filamentous structure are observed in the sky at high altitude. They come in the most diverse forms, either in the form of feathers or ponytails, or in the form of thin flakes of cotton wool with a fibrous structure, or in the form of threads or light, transparent strokes of white paint on blue sky. Sometimes individual clouds are randomly scattered across the sky, sometimes they are bizarrely entangled with each other or arranged in the form of parallel stripes crossing the entire sky or part of it, and, due to perspective, such stripes seem to converge with each other. Such clouds are called cirrus (the international name is Cirrus or Ci for short).

Cirrus clouds are the highest of the upper clouds.

In general, the clouds of the upper tier are usually located at levels above 6,000 meters.

In our latitudes, the upper boundary of the layer of air where the highest "cirrus" clouds form extends to about 11-12 kilometers. Rarely, they are seen slightly higher.

The highest clouds

The layer of the atmosphere from the earth's surface to a height of about 11 kilometers (in our latitudes) called the "troposphere" is characterized by the fact that it decreases with increasing altitude. In the overlying layer, called the "stratosphere", the drop in temperature with height stops. Thus, all clouds observed in the sky float in the troposphere. In the higher layers of the atmosphere, clouds of the usual type are not observed at all.

noctilucent clouds

However, in rare cases, sometimes at enormous heights, faintly luminous, so-called "silvery clouds" appear, the origin of which is still largely mysterious. They are observed in the sky after sunset, when its rays continue obliquely to illuminate the upper layers of the atmosphere in which these clouds float, which is why they seem to glow against the dark background of the sky after sunset.

These clouds were discovered in 1885 shortly after the huge eruption of the Krakatoa volcano (between the islands of Java and Sumatra) in 1883. They floated at an exceptionally high altitude: about 70-80 kilometers. Some scientists have suggested that these clouds are the products of a volcanic eruption thrown to a huge height, consisting mainly of ice crystals formed from water vapor thrown out during the eruption. reflecting Sun rays, they seem to us luminous. However, in the last century (starting from 1926), noctilucent clouds began to be observed again in the sky, but already at a much lower height, namely about 28 kilometers.

Observations of the appearance of noctilucent clouds are important in the sense that they may help to resolve for the time being cryptic question about the reasons for their origin.

Cirrus clouds (Cirrus, Ci) have a thickness from hundreds of meters to several kilometers. They consist of ice crystals in the form of needles, columns, plates. The luminaries shine through them. There are such types of cirrus clouds: filiform, claw-shaped, tower-shaped, dense, flaky, entangled, radial, ridge-like, double .

cirrocumulus clouds (Cirrocumulus, Cc) are characterized by a small width - 200–400 m. The structure of the clouds is lumpy. They are transparent. There are wavy, cumulus with turrets, flaky varieties of cirrocumulus clouds.

Cirrostratus clouds (Cirrostratus, Cs) they look like a white or bluish translucent shroud. Their thickness ranges from 100 m to several kilometers.

Altocumulus (Altocumulus, Ac) they look like white, sometimes grayish waves, consisting of plates or flakes separated by gaps in the blue sky, but they can also merge into a continuous cover. The thickness of the layer of altocumulus clouds is about 200–700 m. Rain and snow fall out of them.

Altostratus clouds (Altostratus, As) form a solid gray or bluish "carpet" in the sky with a lower boundary, usually at an altitude of 3–5 km. The thickness of the cloud layers is 1–2 km.

High-layered translucent (Altostratus translucidus, As trans)

Stratocumulus clouds (Nimbostratus, Ns) - these are gray clouds, consisting of large ridges, waves, plates, separated by gaps or merging into a continuous gray wavy cover. They consist mainly of drops. The layer thickness is from 200 to 800 m. Precipitation, as a rule, does not fall. Stratocumulus clouds are wavy, cumulus, dissecting, vymeobrazny.

Stratus clouds (Stratus, St) they are a uniform gray or gray-yellow cover. There are different types: foggy, wavy and broken. Broken rain clouds are often observed under a veil of stratus clouds.

Nimbostratus the clouds look like a solid gray veil that covers the entire sky in the form of ridges and shafts. They consist of water droplets, rarely mixed with snowflakes. Heavy precipitation falls from this type of cloud.

Cumulus clouds (Cumulus, Cu) divided into cumulus, cumulus medium and cumulus powerful. Thickness 1-2 km, sometimes 3-5 km. The upper parts of cumulus clouds look like domes or towers with rounded outlines.

Cumulonimbus (Cumulonimbus, Cb)- very powerful cloud clusters; they are "bald" and "hairy", with a thunderous arcuate shaft in front.

Clouds of an unusual shape

are rare, most often in the tropics. Their appearance is associated with the formation of tropical cyclones.

also a very rare occurrence.