By: Alex
Last week, Japan’s Mount Fuji witnessed a rare natural phenomenon: its summit was covered by a cap cloud (also known as an umbrella cloud or UFO cloud), making it look as if the mountain was wearing a hat. Even more unusually, the cap cloud appeared in the early morning, accompanied by the sunlight of dawn, with the floating clouds tinted in various colors by the sunrise. This spectacle prompted many photography enthusiasts to sacrifice their sleep—or even skip work the next day—just to “chase the clouds.”
▲(Photo by hiroshi_yamamoto_vh @IG)
The formation of a cap cloud requires strong winds, sufficient humidity, and the right terrain. When cumulus clouds move over the mountaintop and are caught between upward and horizontal high-altitude air currents, a cap cloud forms. The appearance of a cap cloud usually signals that the weather is about to become unstable—for example, with dropping temperatures or rainfall. It’s said that in the past, people would joke that Mount Fuji was wearing a hat to keep off the rain, and they themselves would carry an umbrella when going out.
▲(Photo by hiroshi_yamamoto_vh @IG)
After strong winds pass the mountain peak, similar layered “UFO clouds” can also form on the leeward side. Known meteorologically as lenticular clouds, they come in various shapes, such as cylindrical or oval. Like cap clouds, lenticular clouds don’t move much—they appear and disappear in place—but they can also be a harbinger of approaching bad weather.
▲(Photo by mori_keke @IG)
▲(Photo by _h.joyeuxnoel.k @IG)
▲(Photo by 01ktk15 @IG)
▲(Photo by 01ktk15 @IG)
▲(Photo by hajimeha @IG)
▲(Photo by hashimuki @Twitter)
▲(Photo by hashimuki @Twitter)
▲(Photo by hashimuki @Twitter)
▲(Photo by kaji_photochromism @IG)
Source: 大人物 (Great People)