WHAT’S your favourite cloud? Perhaps it’s one of the stranger formations. Altocumulus lenticularis, maybe, which settles in spooky hoops over high mountain peaks like an alien mothership. Or it could be the simple, humble cumulus, also widely known as the “fair weather cloud”. Surely everyone loves those puffy cotton balls that seem to morph into friendly and familiar shapes – elephants, teapots, diving bells – while you gaze at them against a backdrop of blue sky.
The cumulus evokes the daydreams of childhood, and memories of summer that might be especially precious to those of us who grew up in grey and rainy Northern Europe, under oppressive layers of nimbostratus and altostratus. For me and many others from that dank corner of the world, the first and greatest pleasure of air travel is to speed up, lift off, and blow through that grim ceiling into the sunlight.
“There’s a moment of revelation that you can only get from the window of a plane,” says Gavin Pretor-Pinney, founder of The Cloud Appreciation Society. “When you ascend through an overcast sky and emerge into a different topography, where the clouds look like mountains and valleys, or like an ocean of rolling wave forms. They exist in their own terrain, which defies the logic of the land. As G.K. Chesterton wrote, ‘There are no rules of architecture for a castle in the clouds’.”
In that takeoff phase of flight, Pretor-Pinney always watches out for a complex optical effect known as a “glory”, and recommends you do the same: under certain conditions, the shadow of the aircraft is cast onto the cloud below and encircled by a rainbow-halo, as light is diffused through water vapour into its constituent colours.
He doesn’t claim to be any kind of expert, only an enthusiast. His authority on this subject has been conferred upon him by the growing membership of The Cloud Appreciation Society. What began as a kind of hobby in 2004 – “like a fun art project on the side”, while he worked in publishing and design – has since become a global community of more than 40,000 like-minded cloudspotters. (The society’s handbook, written by Pretor-Pinney, is titled The Cloudspotter’s Guide.)
That number, he says, includes “hardcore scientists, amateur photographers, airline pilots, painters, poets across such a range of ages and nationalities”. “It’s a broad and universal subject, but also very personal. Each of us has our own relationship with the sky, which goes back to finding shapes in the clouds as kids.
“Doing this has made me see the connections between people that have nothing to do with language. We all inhabit the same sky, we’re all creatures of the same atmosphere, and our reactions to the clouds are unifying.”
In practical terms, the society serves as a forum for sharing thoughts, quotations and especially photographs of particularly notable or beautiful formations from above the heads of members. And recently, this gathering of images led to a new discovery. One particular pattern seemed to recur in different locations, and didn’t fit the standard profile of the broad and wavy undulatus cloud. Pretor-Pinney came to believe they may have identified a previously unclassified type.
Following the Latin naming system adopted in the 19th century – the same language used to label plants and animals – he called it “asperatus”, after a passage from the Roman poet Virgil describing a rough sea. Duly submitted for consideration to the World Meteorological Organisation, it was half-confirmed as a new cloud “feature”, rather than a type unto itself, and is scheduled to appear in next year’s updated edition of the International Cloud Atlas.
That book was first published in 1896, when meteorology was a new science and photography a new technology. Revisited every few decades, it is now being adapted to the digital age with its first supplementary online edition, due in March 2017. The Cloud Appreciation Society is already a part and a product of that age, says Pretor-Pinney. “It can only really exist because of the internet, which allows for the sharing of images and information regardless of geographic location.”
“At the same time, I see it as an antidote to some of the difficulties of our present moment. We know all the downsides of being forever connected to stimuli through our devices. We don’t let ourselves get bored any more, we don’t stare off into the distance. But when you’re daydreaming, rather than concentrating, your brain is just as active, and your imagination is drifting in the breeze.
“Cloudspotting is great for that, and so is travel, because it gives you that coasting time, just staring out the window of a train or plane.”
It’s not just the passengers who get the benefits, confirms Mark Vanhoenacker, a commercial long-haul airline captain and author of the recent book Skyfaring: A Journey With A Pilot. Part of his job is to be a professional observer of clouds – to look out for cumulonimbus, for example, and avoid “vertical development” to help keep the flight smooth. But Vanhoenacker is also something of a poet in the cockpit, who appreciates how scattered clouds can “frame the world below”.
Asked about his own favourites, he mentions the low, rolling layers that seem to follow the contours of the Scottish Highlands. “It’s odd to think of those heather-covered hills and the foggy country lanes through them, while we’re racing seven miles above them, in naked sunshine, off to Los Angeles or wherever.”
Even at night, says Vanhoenacker, there is often a good chance of spying a lone, soul-stirring wisp above the ocean, beneath a full moon. “I love those clouds that will never see land, that simply float in the moonlight over the open sea, witnessed by no one, except a few lucky pilots and passengers who happened to look.”