Image: Ken Smith
Pink-tinged lenticular clouds over Mt. Rainier in Washington State
If you’re lucky, you may have already seen the stunning meteorological phenomenon we’re about to explore today. Yet, while lenticular clouds are a rare spectacle for many people, if the conditions are right, it’s not impossible to catch sight of them – and better still, to capture them on camera! Lenticular clouds are quite different from mammatus clouds, featured previously here on Environmental Graffiti, but they’re just as peculiar in shape. In fact, their appearance is so distinctive that to human eyes they are often mistaken as close encounters of the third kind – and looking at these 20 amazing images, we can see why!
Image: Barbara Snow
Southern California’s Colorado Desert: The Perfect place for a UFO sighting!
As is particularly obvious in this photograph, lenticular clouds frequently display two or even more layers, and this tendency, together with the clouds’ smooth and flat appearance, has meant they’re often likened to a stack of pancakes. You’d need a lot of syrup for this stack though…
It’s worth noting that the main scientific name for lenticular clouds is Altocumulus lenticularis, which refers to their appearance – lenticularis meaning ‘lens-shaped’. More colloquially, these clouds are called ‘lennies’. And, when a chain of lenticular clouds appears, each one mounted on the crest of the previous cloud, it creates a formation known as a ‘wave cloud’.
Image: Yaping Wu
A perfect hat for Mt. Hood in Oregon
The smooth, often disk-like shapes of lenticular clouds has also led to them being compared to flying saucers. Indeed, they’ve even been mistaken for real UFOs, or at least some kind of cloaking device for extraterrestrial spacecraft! In fact, according to this BBC article, lenticular clouds are “said to be the single biggest explanation for UFO sightings across the world.” Looking at this image, we can see why!
Image: James Crowe
Aladdin’s lamp, anyone?
There actually are three different types of lenticular clouds, each named according to the level of the atmosphere at which they arise: stratocumulus standing lenticularis (SCSL) occur at lower altitudes, altocumulus standing lenticularis (ACSL) at mid-level altitudes, and cirrocumulus standing lenticular (CCSL) clouds at higher levels of the atmosphere.
As types of stratocumulus clouds, lenticular clouds generally display vertical rather than horizontal growth, which explains why they can rise high up into the atmosphere. Cirrocumulus standing lenticular clouds are usually found at heights of over 24,000 feet (7,315 m)! However, they are extremely rare, as they require a mountain of sufficient height – and not many of them exist – as well as the right meteorological conditions. But more about the connection between lenticular clouds and mountains in a bit.
Image: Tony Gálvez
A menacing lenticular cloud ‘tower’ spotted close to El Calafate in Patagonia, Argentina
The most common lenticular clouds (if one can speak of common when talking about these unusual cloud formations!) are altocumulus standing lenticular clouds, which can be observed at altitudes of between 8,000 and 20,000 feet (2,438 and 6096 m). Stratocumulus standing lenticular clouds, meanwhile, are the low-riders of the bunch, found at heights of around 8,000 feet (2,438 m).
Image: Arne Kaiser
Stuck in the mountains? A lenticular cloud engulfs the San Francisco Peaks in Flagstaff, Arizona
Those who would prefer not to get wet while enjoying a spot of cloud-watching will be happy to know that altocumulus standing lenticular clouds are not usually associated with rain. The reason for this is that they develop where there is more in the way of horizontal flow, with generally drier and more stable air masses.
Image: Cindi Girard
Like a lid on a pot: Lenticular cloud caps this mountain in Oregon.
But how do lenticular clouds like those of the altocumulus variety form? Well, it’s all about the wind – the direction in which it is blowing and what lies in its path. Basically, comparatively stable, fast-moving air is pushed upwards upon meeting a topographic barrier (like a mountain) that is positioned perpendicular to the movement of the upper-level winds. This is why lenticular clouds are more often spotted close to great mountain ranges like the Himalayas, Andes or Rockies.
These beautiful lenticular clouds over Mount Hotaka in Japan almost look like hot air balloons!
The mountain barrier obstructs the upward-streaming winds, and this in turn produces a ‘gravity wave’ (also known as a standing wave) downwind from the mountain. Altocumulus standing lenticularis clouds will form when there is enough moisture in the air above the summit. This is the reason why lenticular clouds are often photographed enshrouding mountaintops (this, and the fact that they look so awesome that shutterbugs can’t get enough of them!)
Image: Jean-Michel Priaux
Scenic Alsace in France, made all the more picturesque by the presence of lenticular clouds hovering overhead
If this picture hasn’t been made into a postcard yet, it really should be! A winter wonderland with highlands in the background and vineyards up front, topped off by a church whose spire seems to tickle the belly of the lenticular cloud formation above it. It doesn’t get much more picturesque than this!
Image: Chris Charlesworth
Doesn’t this lenticular cloud look like the manifestation of a mother ship?
The clear blue sky and the gigantic cloud hovering over a flat landscape make this a very special capture. Even the steel lattice mast atop the tower of Emley Moor transmitting station in West Yorkshire can’t reach this lenticular wonder, and it’s the UK’s tallest freestanding structure, at 330 meters (1,080 ft). How’s that for a high-flying cloud?
Image: Jackson Trappett
A UFO about to land in Mesa County, Colorado?
Despite their love of lofty peaks, lenticular clouds can form away from major mountain ranges – as was the case over West Yorkshire in December 2011. Here, stable but moist air was also responsible; it’s just that rather than being deflected off some towering summit, it had traveled over the more modest low-rising mountain range of England’s Pennines in order for the standing wave to form.
Image: Mel Stoutsenberger
Lenticular clouds over a residential area in Las Vegas
Still, for lenticular clouds, size does matter. According to BBC weather presenter and climate correspondent Paul Hudson, “The bigger the hill or mountain range the air travels across, the more spectacular the lenticular cloud.” Looking at the scale of the lenticular clouds in this picture, the air must have bumped into something pretty sizeable!
Starship Enterprise on fire? Nope! Lenticular cloud near Pahala, Hawaii at dusk.
From what we’ve learned, it seems like lenticular clouds are more or less at a loss without mountain ranges. So it’s probably safe to assume that if one witnesses one of these stunning cloud formations over flat terrain, the lenticular clouds will have traveled some distance from the mountainous region where they developed.
Image: Claudio Sabia
Beautiful lenticular cloud over mountains in Italy’s Friuli–Venezia Giulia region
Although altocumulus lenticular clouds might look as though they are stationary – hovering, perhaps, like a UFO – nothing could be further from the truth. In fact, the clouds are simply forming and dissipating so quickly that the formation appears to remain still. So while the clouds seem to be ‘standing’, given how swiftly winds are moving through them, in reality they are anything but.
Even the Antarctic isn’t safe from alien invasion! These two pinkish, UFO-like lenticular cloud formations look ready to land on the Arctowski Station any minute.
If you’ve already got the urge to go and see some of these meteorological marvels for yourself, here’s a tip: lenticular clouds are observed more in the winter or spring because that’s when winds high up in the air tend to be at their strongest.
Oh, and by the way: the phenomenon of bright colors appearing along the edges of lenticular clouds is called irisation. Irisation takes place when sunlight is diffracted in clouds, resulting in the emergence of various different iridescent colors.
Duck! It’s a UFO over Palm Desert, California!
An interesting tidbit for aviation enthusiasts is the way in which pilots of powered aircraft use lenticular clouds – namely, not at all! Aviators actively avoid straying too close to lenticular clouds because of the extreme turbulence the clouds can bring with their strong upward and downwards moving winds. Better safe than sorry (or airsick)!
Mt. Youtei in Japan, as much cloud-capped as it is snow-capped.
But for pilots of non-powered aircraft, lenticular clouds are a whole different ball game. Or should we say wind game? As opposed to viewing them as no-go areas that might damage their craft, glider pilots may actually seek out lenticular clouds to take advantage of the massive upward lift they offer…
Image: Rob Millenaar
A cluster of alien spaceships scouring the Andes for a place to land?
Apparently, for a glider pilot it is relatively straightforward to predict and pinpoint, simply from the orientation of the clouds, how best to exploit the smooth yet powerful ‘wave lift’ of the rising air mass.
Image: Luca Galuzzi
We’re not sure which is more stunning in this picture – the lenticular cloud formations, or Salar de Talar, a salt flat near San Pedro de Atacama in Chile
In fact, major current world records for gliding were both achieved with the help of the wave lift provided by lenticular clouds. The gliding record for distance is currently 1,864 miles (3,000 km), while that for altitude is 50,721 feet (15,460 m). Whoa – way to go, and way to fly high!
Image: Ed Post
As if the burning pink UFO-like clouds weren’t enough, the barren rocks of the Alabama Hills in Inyo County, CA help this scene look truly alien.
Although we could happily do this all day, our tour of lenticular clouds has to end sometime – so we thought we’d leave you on a high! If you’d like to see formations such as these for yourself, just remember that altocumulus lenticular clouds usually form during daytime when winds are strongest at lenticular-friendly altitudes. Just stake out a suitable mountain and you should be all set. Beats TV any day, doesn’t it?