Types of clouds: formation of storms and other phenomena

Knowing the types of clouds and associating them with weather conditions is essential when doing or planning an outdoor activity, such as mountaineering or skiing. Clouds can be a tool for forecasting short-term weather.

But first of all, how are clouds formed? The clouds are formed by a variable amount of water vapor that is saturated due to a contribution of moisture and a cooling of the air. The condensation of this water vapor in droplets, or in ice crystals form the cloud.

When these droplets increase in size, either by absorption of humidity from the environment, or by collision with other drops; these tend to fall towards the surface pushed by their own weight.

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Clouds can be classified according to their shape and depending on the height at which they are formed.

We can differentiate three types of clouds in relation to their shape:

  • Filiform: white, thin and filamentous clouds.
  • Cumuliform: globose clouds, rounded, shaped like cotton.
  • Strati form: clouds that cover a large area and cover the sky

Once the 3 forms of fundamental clouds are known, we can differentiate up to 10 types of clouds, according to the height at which they form. Each of them has its main characteristics and may develop different weather conditions.

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Cloud Type Chart made by I Love Ski

  1. Low layers: from fogs that are formed close to the surface to those that reach 3 km high in the atmosphere.
  • Strata (St): they form a continuous grayish layer. They can generate drizzles.

  • Stratocumulus (Sc): they form uneven layers, with gray tones and whitish areas. Generally, you can see the sky. They do not generate precipitation.

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  • Clusters: these are isolated and dense clouds, they can produce a slight vertical development. They are known as “Good Weather Clouds”, although they can cause local rains due to the association of several nuclei.

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  1. Medium layers: they are formed in the interval of 3 to 6 km.
  • Altocumulus (Ac): they form a mantle composed of groups of white clouds, shaped like a honeycomb. They allow the view of the sky. They usually don’t produce precipitation.

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  • Altostratus (As): they form a gray veil, uniform, with thicker areas and own shadows. These clouds are formed in fronts that can generate abundant and persistent rainfall.

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  1. High Layers: formed beyond 6 km and can reach the Tropopausa (15 km).
  • Cirrus (Ci): isolated, filamentous and white clouds. They are formed by ice crystals that form at a temperature below -40 ° C. They are a symptom of an approach to a warm front and rainfall within 24-36 hours.

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  • Cirrocumulus (Cc): grouping of cirrus trees which give a “grain shape” to the sky. They generally indicate atmospheric instability and are a symptom of precipitation.

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  • Cirrostratus (Cs): they form a whitish veil in the sky that can cover it partially or totally. They can cause solar and lunar halo phenomena. They usually appear after cirrus when a warm front approaches.

  1. Main development: these occupy two or more of the layers previously seen. They are the types of clouds that generate greater atmospheric instability.
  • Nimbostratos (Ns): they are the clouds that accompany the fronts. They form a dark and dense gray layer, of great superficial extension. They leave moderate and persistent rainfall.

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  • Cumulonimbus: huge cloud masses of vertical development. They are dense and very dark base. Its summit can reach the tropopause. They are storm clouds, which are accompanied by electric shocks. The bottom part is usually composed of water while on the top there are ice crystals. They can cause rain, hail or snow.

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Below you can see an illustrative video where the types of clouds we have just explained are explained in detail:


Types of clouds and their relationship with storms

As we have said, clouds are formed by a contribution of moisture and a cooling of the air masses. So why do storms usually form in summer and in mountain areas?

This is due to a convergence of winds. The sun rising in the east makes it warm on these slopes that causes the hot masses to ascend the slope when they lose density. At noon, especially during summer time, the sun also affects the rest of the slopes, which causes these masses to rise and all converge on top of the mountains.

Once the types of clouds enter the scene and the water droplets form they continue to rise, colliding with each other, producing static electricity. Afterwards, the potential difference can originate lightning, being able to be these middle points of the cloud, with the surface or with the space. The higher the differential, the greater the discharge.

The so-called cold drops are this same phenomenon, but in regions fed by sea moisture. There is a clash between the warm masses of the sea and cold air at high altitude, generating large cumulonimbus.

Let us show you a YouTube video named “TimeLapse – Birth of a Storm”.

Curiosities. Other phenomena

Some of the most unique phenomena are electrometers, which occur when the electricity in the atmosphere is revealed.

  • Northern Lights: are produced by solar emissions of particles charged and channeled by the Earth’s magnetic field in the upper atmosphere. It is observed in polar areas. In the northern hemisphere they are called boreal and in the southern hemispheres.

The auroras have been studied since the seventeenth century, when French astronomer Pierre Gassendi described the phenomenon in southern France. Although they are seen near the poles, the closest one in Ecuador occurred at a latitude of 13º Su in Samoa, in 1921.

  • Fire of San Telmo: it is a light discharge of elastic electricity on objects. This phenomenon has been recorded since the time of Christopher Columbus, when he met this on October 26, 1493:

“On the same Saturday night the Fire of San Telmo was seen, with seven candles burning, above the topsail. With a lot of rain and awful thunder. I mean that you could see the lights that sailors claim to be the body of San Telmo, and they sing many litanies and prayers, taking it for granted that in storms where nothing appears can be in danger”.

Hernando Colón, Second voyage of Columbus

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Snow: what it is and its types