On October 11, images of fragmented, densely packed cloud layers circulated widely on Facebook, covering the sky over Hanoi. According to the post, this cloud formation is referred to as “dragon scale clouds,” which typically forecast an impending storm or signal other extreme weather systems.
This post immediately garnered significant attention from the online community, with many expressing curiosity about the concept of “dragon scale clouds,” while others voiced their fears and suggested ways to avoid the storm.
However, according to meteorologist Nguyen Lan Oanh in an interview with Thanh Niên newspaper, the cloud images observed in Hanoi on October 11 are not mammatus clouds (what locals commonly refer to as “dragon scale clouds”).
Furthermore, through monitoring, there are no signs of storms or extreme weather conditions expected in Hanoi over the next week.
Regarding the cloud images that went viral on social media on October 11, the National Center for Hydro-Meteorological Forecasting indicated that these are altocumulus clouds (Altocumulus translucidus), also known as Ac tr clouds.
Altocumulus clouds resembling a school of mackerel. (Illustrative image).
Altocumulus clouds form in patches, sheets, or layers that are mostly translucent, typically appearing in the positions of the sun or moon. During the initial formation phase, these clouds have a very uniform shape, extending horizontally on average. Within the cloud, smaller elements are evenly arranged to form thin sheets or a checkerboard pattern.
These middle clouds are composed of water droplets due to the low transparency of the larger particles, and when they separate, they have distinctly clear edges. However, under very low temperatures, ice crystals may form.
Generally, altocumulus clouds appear white or gray. They can appear at various altitudes in the same sky and sometimes combine with mid-level clouds. In such cases, fog is often present just below the altocumulus layer among their elements.
