Strange bumps in the sky are natural cloud features, not the results of weather manipulation

On 20 September 2024, TikTok user ‘nizzyconspiracy’ – who has nearly 600,000 followers at the moment – posted a compilation of short video clips showing alien-looking clouds. With the header “This Can’t Be Normal”, nizzyconspiracy’s video claims that these strange skies are the results of an unspecified group “messing with the weather”. In the video, nizzyconspiracy narrates, “There is no way that you can say that this is a normal cloud formation […] We know that clouds are not supposed to do this”. The video has gathered more than 47,000 views and 4,000 likes. A Facebook user later reposted the video as a Facebook Reel, where it has received more than 49,000 views.

But most of the clips in the video depict completely natural cloud features, known as mammatus and asperitas. Meteorologists, professional and amateur alike, are well aware that clouds can develop these features. Both mammatus and asperitas are recognized by the International Cloud Atlas, the world’s most popular reference on cloud types. These features’ alien appearance makes them favorites of cloud photographers. 

In this review, we show that, although meteorologists do not yet have a consensus on how either mammatus and asperitas form, there is no evidence indicating they are the result of weather manipulation. Simply because a phenomenon is not completely understood does not make it the product of a conspiracy.

Mammatus and asperitas are natural

Mammatus, also known as mamma, appear in the sky as udder-like bumps on the bottoms of clouds: hence their name, derived from the Latin for “udder” or “breast”. You’ll often see them called “mammatus clouds”, although mammatus are not clouds themselves, but features that can appear on several different types of clouds.

Cloud-watchers most associate mammatus with cumulonimbus clouds, the tall, dark, and looming anvil-shaped clouds linked to thunderstorms. But it’s possible to spot mammatus on all sorts of clouds, ranging from stratocumulus (gray sheets that can fill the sky on overcast days) to altocumulus (small white puffs) to cirrus (thin high-altitude wisps visible on clear days). Mammatus can even appear on aircraft contrails¹ and volcanic ash clouds².

Scientists generally agree that mammatus form because the air inside a cloud – filled with ice particles and water droplets – is significantly wetter than the drier air that surrounds it, but scientists haven’t formed a consensus about what specifically creates mammatus’ distinctive lobes³. Mammatus may form from wet air rushing out of the cloud, from dry air attempting to mix with the cloud’s wet air, from water droplets within the cloud evaporating into the surrounding drier air, from a combination of these causes, or for another related reason^3,4. Whatever the case, these airflows happen naturally, without human interference.

Perhaps even more alien-appearing than mammatus are asperitas, which look like waves on a stormy sea. Asperitas most frequently appear on the dark bottoms of cumulonimbus storm clouds⁵. Asperitas are significantly rarer than mammatus – in fact, the World Meteorological Organization did not recognize them as a cloud feature until 2017.

Partly for that reason and partly due to their rarity, there hasn’t been much research into how asperitas form. The studies that do exist hint that asperitas and mammatus are related. One theory posits that asperitas result from turbulence at the bottom of a cloud⁵. This kind of turbulence usually occurs atop clouds, which may explain why asperitas are so rare. Another theory is that asperitas form when cloud-borne water droplets move on atmospheric gravity waves, which form where two air masses violently meet – at a thunderstorm, for example^5,6. Again, these are natural occurrences.

There is no reason to believe these are the results of weather manipulation

Weather modification isn’t secret – its most well-known form is cloud seeding, using chemicals to influence how clouds develop. Weather modification today is mostly limited to a few cloud seeding programs aimed at preventing unwanted rainfall or at increasing rainfall in deserts or drought-stricken regions. Some scientists have even proposed creating clouds to reflect more sunlight back into space and mitigate the effects of greenhouse gasses, but such proposals are controversial and nowhere near reality⁷. 

With that in mind, if mammatus and asperitas were linked to weather modification, we might expect to find a good deal of scientific study on the features. On the contrary, mammatus and asperitas are poorly studied. We’ve already spojen about how asperitas have only recently been recognized. Furthermore, meteorologist David M. Schultz and colleagues wrote the following about mammatus:

Because they are not directly related to significant weather events on the ground and they do not apparently hold insights into forecasting severe convective storms, mammatus generally have been viewed as no more than a curiosity in the atmosphere. Consequently, published research on mammatus is rather limited, and what literature exists is either highly speculative or severely constrained by the limited nature of the observations³.

This is despite the fact that mammatus have been scientifically observed for well over a century – well before the development of any modern cloud seeding techniques³.

It can be tempting to explain oddities that scientists don’t completely understand by alluding to conspiracy theories or dramatic mysteries. This is also demonstrated by those who believe that, since we do not fully understand how ancient Egyptian laborers built the pyramids of Giza, the pyramids must have been built with the help of alien visitors. But a phenomenon not being understood is not a reason for making assertions that have no scientific backing at all.

Conclusion

Contrary to the TikTok post’s assertion that “clouds are not supposed to do this”, the cloud features it depicts are actually perfectly natural. Mammatus and asperitas are both cloud phenomena recognized by the World Meteorological Organization. How exactly mammatus and asperitas form in clouds is not well-understood, but human interference in the weather does not cause either phenomenon.

References:

• 1 – Schultz and Hancock (2016) Contrail lobes or mamma?:The importance of correct terminology. Weather.
• 2 – Mastin et al. (2022) Understanding and modeling tephra transport: lessons learned from the 18 May 1980 eruption of Mount St. Helens. Bulletin of Volcanology.
• 3 – Schultz et al. (2006)  The Mysteries of Mammatus Clouds: Observations and Formation Mechanisms. Journal of the Atmospheric Sciences.
• 4 – Ravichandran et al. (2020) Mammatus cloud formation by settling and evaporation. Journal of Fluid Mechanics.
• 5 – Harrison et al. (2017) Asperitas – a newly identified cloud supplementary feature. Weather.
• 6 – Ravichandran and Govindarajan. (2022) Instability driven by settling and evaporation in a shear flow: A model for asperitas clouds. Physical Review Fluids.
• 7 – Gasparini et al. (2021) To what extent can cirrus cloud seeding counteract global warming? Environmental Research Letters.