On August 19th, the skies over Du Hubei, China, witnessed a rare meteorological phenomenon: mammatus clouds. Videos shared on social media quickly went viral due to the peculiar appearance of this phenomenon, which, despite its soft and fluffy look, raised concerns among some people due to its association with the possibility of storms.
Despite the fantastic sight these phenomena offer, very few people know that these are not actually clouds themselves but a unique atmospheric phenomenon.
Mammatus Clouds: What Are They?
Mammatus clouds are distinctive atmospheric formations characterized by their appearance of hanging pouches or bulges. While they may seem strange, they result from strong downward vertical currents colliding and creating an unusual pattern in the clouds.
These formations can develop from various types of clouds, including cirrus, cumulus, stratus, and even stratocumulus. They particularly form from cumulonimbus clouds when a downdraft crushes the cloud against its natural upward formation process. This pressure results in the lower part of the cloud exhibiting bulges called “mammatus,” from which the phenomenon gets its name.
Anvil-shaped cumulonimbus clouds are known for producing especially impressive mammatus clouds that hang from the cloud’s base with their distinctive bulges.
The formation of mammatus is linked to the convective process. All clouds form when warm, less dense air rises as a bubble in the cooler surrounding air, much like a bubble in water. The warm, moist air condenses into tiny droplets, releasing thermal energy into the surrounding environment due to the heat of condensation. This causes the mass of warm air to rise even further. Mammatus clouds occur in the convective phase of dissipation beneath the base of a cumulonimbus cloud.
Unusual Atmospheric Phenomena
Although mammatus clouds may appear intimidating, they are harmless. They often form after intense atmospheric events, such as at the base of a cumulonimbus cloud. The anvil part of the cloud can be considerably larger in relation to the upward-rising portion that triggers the phenomenon. During the dissipation phase, the bulges or “mammatus” can form in the convective region. In areas away from strong updrafts, moisture-saturated air begins to descend with the ice microcrystals it carries.
As it descends, the temperature rises and melts the ice crystals, absorbing heat from the surroundings and moderating the temperature increase due to the air’s descent. Each bulge indicates one of these descending air motions at the cloud’s base. The air just below the cloud base tends to rise due to its warmer temperature compared to the cloud base, and this movement contributes to the formation of the distinctive granular shapes of mammatus.
In summary, mammatus clouds are a rare and fascinating atmospheric phenomenon that may cause concern due to their association with potential storms, although they are actually harmless. These formations are a captivating sight, and despite their intimidating appearance, they pose no threat.
