Imposing wall cloud hangs over Inner Mongolia
This is the moment a huge wall cloud hovered over a city in Inner Mongolia.
The mass of clouds was seen looming over Tongliao City on September 9, followed by a thunderstorm that drenched the area.
According to China Meteorological Channel analyst Walle Hu Xiao, wall clouds are caused by eddies of circulating cold and warm air in a storm.
They form in a process called entrainment, where the updraft of warm air pulls cooler air upward. The colder air is then saturated, causing further cloud development which forms the ‘wall’ that people see.