DEBBIE ELLIOTT, host:
Writer Marq de Villiers has long been obsessed with the wind. It started, he writes, when he was just a little boy living in South Africa.
Mr. MARQ DE VILLIERS (Author): The collision of two ocean currents sends massive pulses of disturbed air into the sky. And the storms they cause coil and twist, boiling up great black thunderheads, tearing the surface off the sea with a howling roar and assaulting the land beyond. On just such a day, the winds seized a helpless child and knocked him down under the grass. Gratuitously, brutally, effortlessly. He struggled to his feet and yelled for help but the gale snatched his breath away and blew it out to sea, stripping away the sound so no one could hear him and the yell became a soundless scream. In the grip of the gale the child skidded across the grass until he landed with a crack against the metal railings that were all the prevented him from being hurled into the ocean. It was there that my mother came and fetched me away and tried to still my terror with her beating heart.
ELLIOTT: In the book Windswept: The Story of Wind and Weather, de Villiers has written a chronicle of the wind, its origins, its mythology and its temperamental nature. The book is both a personal exploration and a scientific handbook. He joins us from the studios of the CDC at Halifax. Thank you for being with us today.
Mr. DE VILLIERS: You're very welcome.
ELLIOTT: Let's start with the basics here. What exactly is wind?
Mr. DE VILLIERS: The simple way of defining wind is that it is simply air in motion. It's the substance called air that is trying to find a balance between pressures, between temperatures, and between gradients. The sun is a nuclear furnace that puts out enormous quantities of heat. Wind moves from cool temperatures to warm temperatures, from low pressure to high pressure, and eventually things balance out, except of course the sun keeps heating us and so winds keep being generated.
ELLIOTT: For centuries people have been trying to predict and explain the weather, dating back before Aristotle. And at first you write people didn't even grasp that wind was the force that was moving weather or storms across continents.
Mr. DE VILLIERS: No, it seems difficult for us to grasp now, but in fact it's not intuitive that wind exists, because unless you know air exists, and early on in early history they had no idea that there was something, they always thought of air as a nothing, and so if there is nothing there, how can it exert force?
And it took that conceptual breakthrough before they really understood that wind was moving air and air had mass and weight. And that was the breakthrough that made - essentially made meteorology possible.
ELLIOTT: When did that happen?
Mr. DE VILLIERS: About three hundred years before Aristotle, so things pretty well stopped there. They still didn't understand what caused wind, because they didn't understand pressure and atmospheric pressure. And so there were some wonderfully fanciful theories developed as to where winds came from. Sometimes the Gods kept them in bags and loosed them malevolently. My favorite was wind was actually caused by seaweed. It was an exhalation of seaweed on the oceans is what actually caused the winds. I rather like this theory and wish it were true.
ELLIOTT: Now, your book is not only a natural history of wind and the way humans have grappled with wind and it's force, it's also the story of Hurricane Ivan, one of the big storms that hit North American in 2004. You actually felt the reach of this storm all the way up in Nova Scotia where you live. I happened to be living in Orange Beach, Alabama at the time of Ivan.
Mr. DE VILLIERS: That was right at landfall, wasn't it.
ELLIOTT: Right. And with all of our ability to watch and prepare for an oncoming storm like that, you write that we still have very little information about why these storms start, and I was struck at your story of the birth of Ivan actually in Darfur in Sudan.
Mr. DE VILLIERS: Darfur in Sudan. It was a pressure system that was created in the mountains of Chad in Sudan. It traveled enormous distances. It didn't begin in the Caribbean or even in the tropical Atlantic. It began in Africa on the eastern side of the Sahara and traveled across the desert there over the cities of Agades and Timbuktu into the ocean, drifted south to the Tropics where it finally picked up its momentum and transformed itself into a fearsome storm within a remarkably short time, two or three days. And then it brushed by Cuba and Jamaica and of course crossed the U.S. coast and Alabama.
But many - the curious thing about hurricanes is it's very difficult to see why one of these systems ends up as a hurricane and another one doesn't. The differences are so small that we can't understand exactly the tipping point of what makes a storm a potential hurricane.
ELLIOTT: You know, there's a question that always comes up in the wake of a hurricane...
Mr. DE VILLIERS: Mm hmm.
ELLIOTT: ...usually in the practical context of dealing with insurance companies.
Mr. DE VILLIERS: Right.
ELLIOTT: But I'd like to pose it to you. When a hurricane blows a wall of water ashore...
Mr. DE VILLIERS: Mm hmm.
ELLIOTT: ...how do you figure out, is it wind or is it water?
(Soundbite of laughter)
Mr. DE VILLIERS: This is a question for the actuaries, I guess. But when it really comes down to it, it is wind, because wind is what creates the storm surge. Storm surges are created partly by low pressure systems in the center of cyclones, which is what a hurricane is, and partly by the simple force - by the sheer force of the wind itself.
And so storm surges can be two or three meters, six, 10, and even 20 feet above normal high tide levels. This is water that's causing the damage, but it's wind that's causing the water to cause the damage. So I would say the insurance companies are being a little disingenuous if they say it's not wind. It is. It's indirectly wind, but it's still wind.
ELLIOTT: I think that's what most hurricane survivors will say, too.
(Soundbite of laughter)
Mr. DE VILLIERS: Yeah, but I'm not sure that the insurance company fine print exactly agrees.
ELLIOTT: Marq de Villiers, today we have the ability to fly into a hurricane, to see what's going on in the eye of the storm. We can even log onto our computers and get a wave height reading from buoys in the middle of the Gulf of Mexico. But are we really able to do more with all of this high-tech forecasting ability?
Mr. DE VILLIERS: We can do a lot more. We know a great deal more about why storms begin and what their mechanisms are and their tracks than we ever did even 15 years ago. But these natural systems are so essentially complicated that there's serious doubt we will ever know enough to credibly be able to steer or control natural systems like storms, and even if we did, that there would be almost apocalyptic ecological consequences. And the best thing we can do with them is to understand them, to track them, to build communities that are able to survive severe storms, and then to let them alone.
ELLIOTT: Marq de Villiers is the author of Windswept: The Story of Wind and Weather. He joined us from the CBC studios in Halifax, Nova Scotia. Thank you for being with us.
Mr. DE VILLIERS: You're very welcome. Thank you.
ELLIOTT: To read about how Marq de Villiers managed to outrun a windstorm on a motorcycle, go to our website, NPR.org. A special thanks to Radio Expeditions for the sound of wind.
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.