Asperitas, rare and surprising clouds that look like waves
The dynamic nature of clouds helps that under certain conditions surprising cloud formations can be generated, and the undulating, unearthly appearance of Asperitas clouds is one of the best examples.
Asperitas are characterized by being undulating, wave-like structures, that form at the bottom of the cloud. These formations usually arise in a chaotic pattern, appearing almost like the surface of a raging sea seen from below. This is what gives them their Latin name, with ‘asperatus’ meaning rough or uneven.
Striking and otherworldly, the rough clouds are actually the latest addition to the International Cloud Atlas from World Meteorological Organization. were added in 2015 after the Cloud Appreciation Society submitted a proposal.
This turned the Asperitas in the first new type of cloud to be named in more than half a century, since they were added cirrus intortus in 1951.
How do rough clouds form?
These clouds are rarely seen and, in fact, there is still no consensus on their formation. They are mainly associated with stratocumulus and altocumulus, and are closely related to the more common cloud waves undulatus or the hanging protuberances of the mammatus.
Although they can be observed in stable conditions, the Asperitas appear more frequently coinciding with storm situations and it is clear that they are needed unstable weather conditions for them to form Although they can be seen near storm clouds, they do not produce precipitation, despite their menacing appearance.
They are thought to form when descending mammatus clouds reach a level in the atmosphere where the wind direction changes.. This could cause their dangling structures to transform into wavy patterns, producing the distinctive asperite formation.
In general, rough clouds They form below 2000 meters, although they can form at higher altitudes when they appear with altocumulus.
Where and when can they be seen?
Asperites can form in many regions of the planet, but they are somewhat elusive, which makes them difficult to see. Since they are often associated with convective storms, one of the best places to see them is in the interior of North America, specifically on the Great Plains of the United States.
In Spain they usually appear in spring or summer, although you have to be very careful to see them, as they dissipate quickly.
In Spain they have also been sighted, and especially in spring and summer, mainly coinciding with situations of instability. The best time to look for them is in the hours after a thunderstorm, but you will have to be very careful if you want to take a picture of them, since they usually dissipate fairly quickly.