OREANDA-NEWS  A cloud tsunami appeared in the sky over Khabarovsk. A rare weather phenomenon is reported by Vesti.

Roller clouds, also known as a thunderstorm collar, covered the city. Clouds seemed to surround Khabarovsk with a giant wall, which is preparing to collapse on the ground. According to experts, a thunderstorm collar is formed when warm and cold air masses collide. In this case, the cold air does not move upward, but is "rolled up" by the tube under the warm air.

Earlier, residents of Kazan noticed a frightening atmospheric phenomenon. The sky was covered with dense clouds, forming a long and clear strip. Such clouds are called a squall gate. Such a phenomenon can signal a powerful thunderstorm, strong wind, or a storm.

In mid—July, another unusual type of clouds was seen over Moscow - mammatus. These clouds occur infrequently and are characterized by a baggy shape resembling an udder. Such clouds appear in the sky due to sudden temperature fluctuations.