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New Cloud to Be Added to the International Cloud Atlas

This cloud makes it look like you are underwater.

| 2 min read

This cloud makes it look like you are underwater.

If you are cloudy savvy like me, then you probably know that there are many different types of clouds — nearly 100 different combinations of genera, species, and varieties.  Now, for the first time since 1951, the International Cloud Atlas is looking to add a new one to that list.  Enter undulatus asperatus — the new cloud in town!

How different clouds form is a fairly complex process, but to simplify things, it basically comes down to water.  Clouds are made of tiny droplets of water or ice that attach to cloud condensation nuclei, such as salt and dust particles in the atmosphere.  Since these droplets are so small and not purely composed of water, they can remain in liquid form at temperatures as low as -22 degrees Fahrenheit (-30 degrees Celsius).

Clouds will form when the air is saturated (full of water) and cannot hold any more, and this happens in two ways: the amount of water in the air has increased or the air has cooled to its dew point (temperature at which dew forms).  

SEE ALSO: Why Do Nuclear Bombs Form Mushroom Shaped Clouds?

So what causes air to rise and clouds to form?  Five things: surface heating, topography, a front, converging air, and/or turbulence.  The range and variety of these variables result in the many sizes and shapes of clouds we see in the sky.

Researchers are still investigating the conditions needed for undulatus asperatus to form, but they do know they are seen most often in the morning or midday following thunderstorm activity.

The man behind the campaign to officially classify undulatus asperatus is Gavin Pretor-Pinney, the founder of the US Cloud Appreciation Society.  “They struck me as being rather different from the normal undulates clouds,” he said to The Verge.  “They were more turbulent, more confused — as if you were underneath the water looking up toward the surface when the sea is particularly disturbed and chaotic.”

The World Meteorological Organization, which governs the International Cloud Atlas, have proposed an official definition, which usually indicates they will make a new addition.  It would mark the first time a new cloud has been added to the atlas since 1951.  The proposed definition is as follows:

A formation made up of well-defined, wavelike structures in the underside of the cloud, more chaotic and with less horizontal organisation than undulatus. Asperatus is characterised by localised waves in the cloud base, either smooth or dappled with smaller features, sometimes descending into sharp points, as if viewing a roughened sea surface from below. Varying levels of illumination and thickness of cloud can lead to dramatic visual effects.

To see these clouds in action, watch the YouTube video below, filmed by anesthesiologist Alan Walters over Augusta, Georgia and uploaded by Natalie Waters.  It is time-lapse footage, filmed on an iPhone 6, of these spectacular undulatus asperatus clouds.



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