Despite the general label we tend to give to them, clouds, as a type of formation, have an incredible amount of variety to them.
You have your classic cumulus clouds, of the small, white and puffy variety, but you also have your cirrus clouds, those thin, feathery, and wispy varieties that form on a warm current.
You have your cumulonimbus titans that generate massive rain and thunderstorms. Then there are your altocumulus clouds, the ones that resemble a patchwork of wool or cotton in the sky.
Then you have the strange ones that always seem to look a little odd. Ones that, although you see them often enough in the sky, just have a texture or formation to them that makes them stand out from other kinds of clouds.
We already mentioned a few unique formations, such as the cirrus and cumulonimbus clouds, but a perfect example of just how strange clouds can look sometimes is the Mammatus cloud.
No, it is not a cloud that looks hairy like a mammoth, or is big and one that is ‘mammoth’ in size or proportions. They often appear bulbous, almost pouch or ball-like, and can have dark patches that are separated by lines of lighter clouds.
If you’ve seen one, you know what we’re talking about.
But what are the forces behind this particular formation? What exactly are they? How do they form? Is there particular weather that is most often associated with them?
Well, that’s what we are going to cover in this guide!
In this piece, we are going to give a brief overview of what this particular kind of cloud is, how it normally is formed in the sky, and what types of weather conditions can be a sign.
What Is A Mammatus Cloud?
Before we go into any detail on how these particular clouds are formed, or what if any weather conditions they are usually a sign of, we should probably explain what a Mammatus cloud is in the first place.
As we have already mentioned in the introduction, Mammatus clouds tend to appear in small dense clusters of clouds, that can have a variety of textures, from slightly wispy, to jagged, and smooth, grape-like clusters.
These clouds tend to form at the base of a formation for a different species of cloud, though they mostly appear under large, heavier types.
This is the reason that many often appear quite dark, especially if they form under a large species, such as a cumulonimbus formation, especially the anvil cloud variety.
The protrusions often catch a little of the surrounding light, giving them an almost ethereal appearance sometimes, especially during sunrises or sunsets.
How They Form
So, now that we have at least covered some of the basics of this type of cloud, now we can go into a little more detail on how exactly they are formed.
However, explaining how this type of cloud forms has puzzled many meteorologists and other weather and climate scientists, because they tend to form alongside or underneath other formations of cloud.
Given how most of these varieties form under different circumstances, it suggests that how Mammatus clouds form is also different, depending on what cloud formation it forms alongside
The following are some of the suggestions that scientists have put forward for how different Mammatus clouds form.
Because Mammatus clouds form on the underside of large anvil cumulonimbus clouds, it has been proposed that as some of the cold air at the top of the cloud falls, it warms.
But because the warming air is still interacting with the rest of the colder clouds, it creates a strange convection imbalance, resulting in the strange lumpy clouds.
However, given that it has been hard to prove that these formations aren’t supporting any major subsidence, it is hard to be definitive with this answer.
Some have suggested that, if the base of the cloud exists near a freezing temperature, then cooling can result in a convective overturning developing, creating a round, lumpy cloud structure.
Given that this isn’t the case for all or most Mammatus clouds, this idea has its rebukes.
Mammatus Cloud Weather Conditions
Whatever the reason by behind their formation, we do know that these Mammatus clouds tend to form alongside very large and heavy rain clouds, such as cumulonimbus formations.
Because of this, Mammatus clouds are often seen alongside heavy rainstorms and thunderstorms. People across history have often seen them as a sign of a bad omen, or bad weather ahead.
So, there you have it. These mysterious clouds are often a sign of bad weather, and that’s all we know for sure right now. But as research continues, the answers may yet present themselves from this cloud formation.