If you think you've just seen a UFO, look again -- what you're probably looking at as a lenticular cloud, a unusual and eerie cloud formation often mistaken for extraterrestrial flying saucers. And plenty of people in Cape Town had to do a double-take when the phenomenon appeared over the South African city this weekend.
Social media was littered with photos of the unusual cloud formation, which appeared over Cape Town on Sunday. Residents in the city snapped photos aplenty and quipped that the natural phenomenon resembled UFOs -- which they do.
Cape Town resident Monique Jackson described them as "massive UFO type clouds" that "became more defined as time passed," CNN added. But, obviously, the unusual cloud didn't contain a single alien and its spacecraft, though it's fun to imagine it did.Once the photos of the cloud emerged online, meteorologists piped up to explain the unusual phenomena over Cape Town as something perfectly ordinary and explainable. ABC meteorologist Daniel Peck said they were "pretty common and pretty cool," and identified them as lenticular clouds, which often form near mountain ranges.
And Cape Town has plenty of them. The city is known for its mountains and valleys, most famously the 3,500-foot Table Mountain, National Geographic added.
The way this formation was created in the daytime sky over Cape Town is quite fascinating, explained Earth Sky. The cloud begins with stable, moist air, which flows over a mountain or a mountain range. Large standing waves then form on the mountain's downwind side. Then the following condition must be met: the temperature of the wave's crest must drop to the dew point, which causes the air's moisture to condense. If that happens, you get an unusual lenticular cloud, which can appear and disappear pretty fast -- as air dips into the wave's trench, the cloud may evaporate.eNCA meteorologist Annette Venter explained the lens-shaped formation this way: "This occurs when stable, moist air flows over a mountain, creating a series of oscillating waves. If the temperature at the crest of the wave equals the dew point temperature, condensation occurs in a lens formation. As the air falls down the trough of the wave, where the temperature and dew point temperature are not equal, evaporation occurs."
And because nature likes to be unpredictable, the clouds generally form over mountainous terrain -- like the terrain that surrounds Cape Town -- but is also known to form in low-lying or flat areas. In these cases, the lenticular cloud is created by the shear winds ushered in by a front.
The unusual sight over Cape Town is dubbed stratocumulus standing lenticularis, which describes both their height and shape. The term lenticular is Latin for lens-like. Cape Town resident Di Brown had another interesting description for the sight: "a tornado on pause mode."
But the unusual cloud has inspired reports of UFO sightings many times over in many parts of the world, as have hole-punch clouds (these are formed by mini snowstorms in "thin, subfreezing cloud layers," NatGeo explained).In fact, when the other-worldly clouds swirled over Texas early this summer, reports of UFOs skyrocketed to 56 sightings in just one month, the Houston Chronicle reported at the time. Because Central Texas is flat, a local meteorologist explained their unusual formation as caused by a massive storm that left a cool air mass in its wake, which "acted like a mountain." Warmer currents of air were "caught in twisting winds in the sky."
Texans were so adamant that spaceships had filled the skies that a report was filed with the Mutual UFO Network, the world's biggest investigative body on the sightings. Over in Cape Town, residents apparently only thought the unusual formation resembled a UFO, but don't appear to have reported sightings en masse.
[Photo Via YouTube Screengrab]