'UFO Clouds' Are Real. Here's How They Happen
Technically called “lenticular clouds,” the weird phenomenon seen over Cape Town has a simple explanation.
Social media users in Cape Town, South Africa, posted photos over the weekend that call to mind classic alien invasion movies. The pictures feature eerie, saucer-shaped puffs that seem to hang over the sky like UFOs.
But these so-called “UFO clouds” are nothing to fear.
Meteorologists call them lenticular clouds, which form when strong, moist winds blow over rough terrain, such as mountains or valleys. Picturesque Cape Town is framed by such features, including the 3,500-foot (1,066-meter) Table Mountain.
(See more cloud pictures and learn about the science of mirages.)
As the wind flows over large features it may cool, causing it to condense into disk-shaped clouds that develop perpendicular to the direction of the air flow.
The clouds in the latest viral photos are
