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  One of the Schenectady experiments centered on an artificial, supercooled cloud that was kept suspended in a freezer. Langmuir was trying to coax the water droplets to crystallize without having to lower the temperature of the freezer to -40°C. Schaefer was running the expermiment and had been adding various chemicals to the cloud chamber without success. On a very hot day in July 1946, the freezer motor seemed to be laboring to maintain the supercooled cloud, so Schaefer thought he’d expedite the cooling process by dropping a chunk of dry ice into the freezer. The experimental cloud instantly crystallized; he could see the light glinting from millions of sparkling crystals still suspended in the air. He tried smaller and smaller pieces, discovering that ridiculously small amounts still triggered the mass crystallization process. The dry ice initiated a sort of chain reaction where the results far exceeded the input. This was a breakthrough.

  Langmuir, upon hearing about the crystallization reaction from Schaefer, immediately realized the potential: “We’ve got to get into the atmosphere and see if we can do things with natural clouds.” On November 13, 1946, they rented an airplane, and Schaefer flew through a cold cloud hovering over the Berkshires. He dumped six pounds of dry-ice pellets over a three-mile section of the cloud as Langmuir watched with binoculars from an airport control tower several miles away. What Langmuir saw amazed him. Snow began to fall from the cloud in thick, white columns.

  Kurt Vonnegut must have sent out the press release that afternoon, because the very next day the New York Times ran a very enthusiastic piece about the breakthrough. A few months later, in January 1947, Bernard Vonnegut discovered that silver iodide was even more effective than dry ice. Speculation in the press ran amok: custom blizzards could be delivered to ski resorts, drought-stricken farmers could irrigate their land with snow. The commercial potential was enormous, and Langmuir and his team were on the verge of becoming very wealthy. Then, in February 1947, the defense department made its move — all cloud-seeding experimentation was transferred to military jurisdiction and the Schenectady lab was shut down. The code name for the cloud-seeding initiative was Project Cirrus. If it was successful, they could weaponize the weather.

  The sky was the limit in the early days of Project Cirrus or, perhaps more correctly, the stratosphere was the limit. Drunk with hubris, the defense department looked for a suitable demonstration of the power they now possessed. They needed a worthy adversary — a really big cloud. What if they could tame the mightiest storm nature could throw at them and subdue the fury of a hurricane? After all, a hurricane is simply a linked series of giant cumulonimbus clouds, and cumulonimbus clouds could easily be seeded.

  The Cape Sable Hurricane

  In October 1947, the perfect opportunity presented itself — the eighth hurricane of the season. After making landfall in southern Florida at Cape Sable, it sped northeastward over southern Florida, causing major flooding, and then headed out to sea. On the morning of October 13, when the hurricane was 350 miles offshore and presumed to no longer be a threat to any inhabited regions, Project Cirrus launched three aircraft carrying 180 pounds of dry ice. When they arrived at the storm, Lieutenant Commander Daniel Rex had the aircraft drop 80 pounds of dry ice on the southwest portion of the shelf cloud. He then targeted two convective towers, 60,000-foot cumulonimbus clouds, with 50 pounds each. Almost instantly, the clouds began to transform. He reported a “pronounced modification of the cloud deck seeded.”

  The dry-ice dump affected almost 300 square miles of the storm’s cloud shield, and the airplanes headed back to their base in Tampa, Florida. According to plan, the seeding should have destabilized the convective flow of the hurricane, causing it to dissipate or at least lose strength. Instead, on the evening of the 14th, the storm pivoted and changed course, heading straight back to Georgia where it made landfall the next morning. Fortunately, it was only a category 1 hurricane when it hit. Although 1,500 buildings were damaged, there was no significant flooding. Project Cirrus was quietly canceled.

  But the U.S. military was not finished with its weaponized weather mandate. Its final use of cloud seeding was during the Vietnam War: a covert offensive named Operation Popeye initiated in March 1967. For the next five years, the 54th Weather Reconnaissance Squadron regularly seeded late-season monsoon clouds over the Ho Chi Minh Trail, extending the rainy period by 30 to 45 days and making life miserable for Vietcong soldiers using the trail. The slogan for the operation was “make mud, not war.” Five years after Operation Popeye was shelved in 1972, during the Environmental Modification Convention in Geneva, the U.S. signed the international treaty banning weather warfare. The treaty came into effect in 1978.

  Even so, commercial cloud seeding continued throughout this period. After the failure of Project Cirrus, cloud-seeding technology became available to commercial businesses. The longest-lasting weather modification company in the United States, North American Weather Consultants, got its start in 1950 and has been seeding clouds over Utah ever since. Today it is a flourishing company, and weather scientists in Utah estimate its efforts add about 250,000 acre-feet to state rivers and reservoirs annually. North American Weather Consultants is just one of many rainmaking enterprises. Cloud seeding in the United States today is almost as routine as crop dusting. Many other countries, including Australia, Morocco, Senegal, Germany, Russia, Kuwait, United Arab Emirates, India, Indonesia, Malaysia and Thailand, have also invested in weather modification technology. But the world’s biggest cloud-seeding operations are in the People’s Republic of China, where rockets loaded with silver iodide are fired into clouds. During the 2008 Summer Olympics, they squeezed the rain out of clouds upwind of Beijing in order to ensure dry weather for the opening and closing ceremonies.

  Of course, if there are no clouds, weather modification is out of the question. There are places in the world that haven’t seen clouds, let alone rain, for decades. One of these, perhaps the driest city in the world is Arica, Chile, located at the north end of the Atacama desert. Even though it is on the Pacific coast, and next to mountains that should provide plentiful orographic rainfall, it is bone dry. During one 14-year period, from 1903 to 1917, it didn’t get a drop of rain. And in the interior reaches of the Atacama are regions where rain hasn’t fallen in 400 years.

  This sounds like a meteorological contradiction, but it isn’t. The hyperaridity of the Atacama desert is a result of the convergence of three climatic factors. First of all, it is in the middle of the South Pacific anticyclone high-pressure zone, a semipermanent region of sunny weather. Second, the cold Humboldt current upwelling offshore prevents any convective cloud formation over the ocean. And third, the region is the unfortunate victim of a reverse rainshadow effect working from east to west — the Andes block any moisture coming in from the Amazon rainforests.

  The Heavens Open

  Curiously, another Chilean town called Bahía Felíx, located some 2,500 miles south at the opposite end of Chile, is the world-record holder for rainy days, with an average of 325 rainy days a year. How could one country contain such extremes of precipitation? Chile is deceptively sized. Though narrow, it is long. If you reversed Chile from south to north and transposed it by latitude onto North America, then Bahía Felíx would sit in Hudson Bay and Arica would be next to Jamaica.

  The uniqueness of arid Arica is exemplified when you compare it to some of the rainiest places on Earth, many of which lie on the windward side of mountains, especially those on the Pacific Ocean. Port Renfrew, for instance, on the west coast of Vancouver Island, gets 138 inches a year. But the western side of Mount Waialeale on the island of Kauai, Hawaii, in the middle of the tropical Pacific gets three times as much, about 460 inches per annum. Réunion Island in the Indian Ocean also gets massive rainfalls. In one 24-hour period, March 15–16, 1952, the town of Cilaos received 74 inches of rain. The current world-record holder for annual rainfall is a village called Cherrapunji in northeastern India: it received 1,042 inches of monsoon rain in 1860. A rec
ord that is still unbroken.

  I’m not sure what the local idiomatic term for heavy rain is in Cherranpunji, but in North America, during a heavy rain, people say that it’s raining cats and dogs or bucketing. Welsh downpours come in old women and walking sticks, and Czechs and Slovaks say it’s raining wheelbarrows. Australians call a hard rain a frog strangler, and in Scotland, a torrential rain is said to be chuckin’ it doon. Greeks say it’s raining chair legs while in Germany a significant rain comes down in young cobblers.

  Nero’s Rain Palace

  Leave it to the Romans to turn the concept of shelter inside out or, should I say, outside in. The Julio-Claudian dynasty, which began with Augustus and ended with Nero, was famous for its excesses. Nero embodied the pinnacle of imperial immoderation. He fancied himself a superlative singer, often competing in musical competitions as far afield as Greece. Nero also held private concerts for the nobility in Rome. According to the Roman historian Suetonius in his tell-all The Lives of the Caesars, the only way to escape the tedium of Nero’s lengthy solo performances was to feign death or jump from second-story lavatory windows.

  Nero, like many other Roman emperors, took an interest in architecture. He loved to pore over scale models with his personal architect, and he was particularly keen on an ambitious design for a palace he’d spent years sketching out. But vacant real estate was in short supply in Rome, and there was nowhere to erect such a large building. Until 64 CE, that is.

  Since the fiddle had yet to be invented, it is impossible that Nero played it while Rome burned. He did, however, take the opportunity presented by the freshly available land in the center of Rome to construct his architectural fantasy. He named his palace Domus Aurea, and it was centered on a grand hall, the coenatio, where Nero appeared during private rituals celebrating his deification. Above him, inside the domed ceiling of the coenatio, he commissioned two of Rome’s foremost architects, Severus and Celer, to build a series of nested semispherical, rotating domes that simulated the movement of the planets in the night sky. As Suetonius wrote, “The main chamber was round and revolved continually day and night, as does the world.” Nero also had his engineers incorporate an ingenious network of metal tubing into the mobile domes so that, on his command, rain would fall from his artificial sky.

  Seneca, who was Nero’s preceptor, described these mechanisms: “A technician invented a system by which saffron-colored water poured down from a great height and also succeeded in assembling the panels of this chamber’s ceiling in such a way that it changed at will.” Unhappily for Nero, he was despised by the Flavian dynasty that supplanted him after his suicide, and his works were destroyed in a retributive policy of damnatio memoriae. His magnificent coenatio along with the rest of the Domus Aurea was reduced to rubble.

  Freezing Rain

  Ice storms are destructive, delicate creatures, requiring perfect conditions before they can deploy their dangerous alchemy. First of all, the surface temperature has to hold at between -1°C and 1°C for the duration of the ice storm, which usually lasts 12 to 20 hours. High above the ground, the clouds have to be stratified with exactly the right thermoclines — alternating layers of warm and cold air — to ensure that the rain becomes supercooled just as it leaves the cloud. Finally, freezing rain is enhanced if the temperature of things on the surface — trees, roofs, cars, buildings — has been maintained at below-freezing temperatures for at least 24 hours prior to the storm. This subzero reservoir makes the supercooled rain freeze on contact, like transparent glue falling from the sky. After that it’s just a question of accumulation.

  When a tree branch or a power-transmission wire is coated with ice, its surface as well as its mass is multiplied. This means that the load factor increases exponentially with every centimeter of ice that adheres, doubling and then quadrupling the pull of Earth’s gravity, an inexorable, devastating force. Ice storms should really be called gravity storms.

  For trees, the destruction from a moderate ice storm is the same as that produced by an F3 tornado, with every tree sustaining some damage and many trees losing main branches. The difference is that the path of an F3 tornado is normally less than a hundred feet across and a mile or two long at the most. By contrast, the great ice storm of January 1998, which struck eastern North America, affected thousands of square miles. During that storm, four inches of freezing rain collected on everything in the system’s path; hydro towers crumpled and whole forests in eastern Ontario, southern Quebec and upper New York state splintered into kindling. More than three million people were left without power for days, and thousands were without power for weeks afterward. The overall damage amounted to $1.4 billion. I missed that one, but I’ve been through several others.

  Ice storms can seem innocuous at first. The rain — usually light, always steady — often sets up the evening before the storm. That was true of the most recent ice storm I experienced in Toronto a few years ago. Just after sunset, the ice storm began in a spectral quietude, a hush that arrived with the misty precipitation. It was hard to tell at first if the rain was indeed freezing, but then, later that night, I opened a window and heard the unmistakable sound of ice creaking as a mild breeze swayed the branches.

  I wasn’t sure how serious the storm was until the next morning. Around 7:30, I was woken up by a loud cracking noise followed by a glassy crash, as if a car had driven through a plate glass window just a few houses away. Minutes later, the same noise. I looked out the window. The trees were collapsing. I put on my bathrobe and went outside. Some of my neighbors were already sprinkling salt on their steps and gawking at the devastation. “At least we still have power,” said Evelyn from across the street. It was a cataclysmic scene: huge branches down and a severed power wire sparking on the ice at the end of the block. One of the bigger branches had crushed the rear of a parked car; another lay across the street, completely blocking it. Everything was coated with ice. It was surreal, apocalyptic. When I went back, I found that the power was out.

  I started a fire and carried in several armfuls of what little firewood I still had in the garage. My fireplace would be my only source of heat. If the blackout went on for too long and the temperature dropped, my pipes might freeze along with my indoor plants. Ice storms are the reason many of my neighbors had invested in gas fireplaces — during a blackout, the gas still flows.

  Fortunately, the power came back on a few hours later, although my house had started to chill despite my cheery fire. That night, I heard more crashing branches, but the next morning revealed an entirely different scene. A cold front had moved in overnight, the temperature had plunged and skies were blue. My backyard had transformed into an dazzling tableau of cut crystal. The icy branches and phone wires sparkled with rainbow prisms in the sunlight. (I noticed that the hues of the ice spectrum were confined to two colors — yellow and purple — a result, I’m guessing, of the limited refractive properties of frozen rain.) By noon, the ice began to fall from the sun-warmed branches, clattering down on the sidewalks and icy yards. By sunset, the neighborhood was littered with drifts of split ice tubes: perfect molds of the branches and wires they had once clung to.

  5

  The Secret Life of Storms

  “I saw the lightning’s gleaming rod

  Reach forth and write upon the sky

  The awful autograph of God.”

  Joaquin Miller

  Our storm-prone globe would be a hard sell for interstellar real estate agents. Imagine a pair of newly married aliens, eager to buy a house and start a family on our lovely blue planet. Everything looks good as their agent goes over the selling points: plenty of water, equitable mean global temperature of 14°C, lots of fascinating life-forms and landscapes — a virtual paradise. The politics and economics of the earthlings hold little interest for the aliens, but their attention is piqued when the agent begins to describe planetary atmospheric conditions. “Statistically speaking,” he says, “the atmosphere is quite hospitable.” Then
he adds that there are “very occasionally” (as he is quick to qualify) “weather disturbances referred to as storms. Nothing really to worry about, though some of them are quite a nuisance.”

  “Now I am worried,” says the female alien. “What kind of nuisance?”

  The agent looks uncomfortable. He elaborates, “Well, most storms involve an electrical phenomenon called lightning, large bursts of energy that conduct a differential charge from the cloud to high points directly under the storm.” He has her full attention.

  “How large?” she asks.

  “In the order of several hundred million volts,” he replies.

  Eventually they wheedle the ugly truth out of him, not just about lightning but also hurricanes, tornadoes, hail, typhoons and monsoon rains. The planet is riddled with storms that can strike anywhere at random, on land or sea. In fact, at any given moment, there are about 2,000 active thunderstorms worldwide, and the human population has no control over them whatsoever. The deal-killer for our alien couple is learning that storms kill hundreds, sometimes thousands of earthlings every year.

  “What about Mars?” the male alien asks. “We passed it on the way in.”

  “Well,” the agent replies, “I must caution you that it does have dust storms, a lot of sand and wind, but no lightning and nothing like hurricanes or tornadoes. Just a few oversize dust devils. It’s cold, dry and has lovely, pastel sunsets. You might like it.” Seeing their polite hesitation, he adds, “At any rate, we have another office quite nearby actually, in the Alpha Centauri system, just a little over four light years from here.”