Windswept: The Story of Wind and Weather - Marq de Villiers (2006)
Chapter 6. The Most Furious Gale
Ivan's story: On September 7, Hurricane Ivan briefly dropped down to a Category 2 storm, but as it pushed west past Grenada in the Lesser Antilles it intensified suddenly and dramatically. The central low pressure went down as far as g47 millibars and the winds in the eyewall were estimated at 135 miles an hour, making it a Category 4.
For the next two days there was a dissonance between the violent drama of what was actually happening on the ground and the dispassionate analyses of theforecasters' technical memos. In Grenada, twelve people died in the storm; students at a local school spent a night wrapped in mattresses under their beds as the roof and the windows peeled away with terrible shrieking sounds; the seventeenth-century jail, picturesque from the outside but crumbling and overcrowded on the inside, was demolished and the prisoners, including the former deputy prime minister, incarcerated for killings in an abortive ig83 coup, fled into the streets. The weather was so bad some of them took refuge in a public shelter in Grand Anse, just outside the capital of St. George's. Others took up machetes and went on a looting spree, perhaps intent on proving that their original sentences were just. Ninety percent of the island's homes were damaged; the prime minister, who took refuge on a British Navy frigate, had his own home completely fattened. Every major building in the capital suffered structural damage; even concrete structures became piles of rubble; wood and iron buildings often disappeared completely.
The same day Ivan had slammed into Barbados and St. Vincent, cutting power and demolishing buildings; in Tobago, a pregnant woman was killed when a forty-foot palm tree smashed through her window and landed on her bed. The storm brushed by the Netherlands Antilles islands of Bonaire, Curacao, and Aruba, flooded parts of the Venezuelan coast, and then headed off, at a leisurely 17 miles an hour, bearing northwest. It seemed to be heading for western Haiti. Or for Jamaica. Or maybe Cuba.
I was watching the technical discussions on the Web with intense interest. The meteorological context was complicated and difficult to predict. It was not just that it was coming hard on the heels of Hurricane Frances, which killed two people in the Bahamas and as many as fourteen in Florida and Georgia; the remnants of Frances were still causing flooding in the southeastern United States, those remnants separated from Ivan's track by that same stable ridge of a strong subtropical high, oriented southwest—northeast. The behavior of that ridge was crucial to understanding what would happen next. It could keep the storms separated. Or it could force Ivan into a radical turn to the right, steering it through Cuba and the Bahamas but thence harmlessly out to sea. Or, if the ridge lifted, Ivan could merge with Frances, with even more unpredictable consequences.
Still, the forecasters predicted possible passage over Jamaica and Cuba, and possible intensification. Any modification in intensity would come only through internal convective changes, entirely unpredictable, or through the tripping effect of a landmass. But the water ahead of Ivan was only forecast to get warmer—as warm as 300 Celsius south of Cuba and in the Florida Straits—and the storm needed warm water to keep going. After that, everything was the sheerest guesswork. But the track was unnervingly close to that of Charley, earlier in the season. Which meant Florida.
Again.
Early on September g, a fine summer day with an early-morning shower and a warm sunny afternoon in the American northeast, Ivan drifted into the eastern Caribbean Sea. At five A.M. it was just north of western Venezuela, at 70° west and 140 north. The central pressure of g22 millibars had dropped 13 millibars in seven hours, and a dropsonde into the eye recorded surface winds at 140 knots. That made the winds 160 miles an hour, and Ivan was upgraded to a Category 3.
That was as high as the classification system went.
I
One way of getting a feel for the force of the wind, as I found to my early sorrow, is to be seized by a gale and almost hurled into the ocean, there (the childish imagination working in overdrive) to be dashed to pieces on the rocks by waves the size of small mountains … But there are easier ways too, and occasions much more pleasant. You can stand, for example, on the pitching deck of a great sailing schooner in a heavy wind, several acres of mainsail billowing out above you, "taught and tight as the steel door of a safe," as actor Sterling Hayden once put it, the wind caught in a capacious cup of canvas to pull a hundred and more tons of vessel through the water at better than 10 knots, bending the massive mainmast almost beyond its tolerances. I once read how in 1780 a British man-of-war rounded the Horn in a gale strong enough to shred any vestige of canvas, and, desperate to turn the vessel, the captain sent a dozen men scuttling up the ratlines to the mainmast yardarms, there to act as a small scrap of clinging living canvas, tiny in relation to the size of the ship but enough, in that force of wind, to give the captain some purchase against the storm.1
Sometimes, if your mood is right, such winds can seem playful. When the wind is gusting to 80 and 90 miles an hour, scudding along a beach, you can go out into the gale, spread your coat into the wind, and bound down the sand in strides that are thirty and even forty feet long, without effort. (Gerry Forbes, head of Environment Canada's Sable Island Station, has done this many times as hurricanes have passed by. "Of course," he says, "you then have to crawl back.")2 At 120 miles an hour, the wind equals the earth's gravitational force, and then you will fly, whether you want to or not. Antarctic explorer Paul Doherty remembers how in a gale station staff would amuse themselves by going out into the hurricane-force winds, facing downwind, and then leaning backward, "leaning on the wind," at angles of 40 or 45 degrees. If someone then creeps up behind you and steals your wind, you'll fall flat on your back. "[A geologist] did this to me twice before I figured out what was going on," he writes. The first year he was at McMurdo Station on Ross Island, Doherty recalls, there was an iceberg one hundred miles long by twenty miles wide, "just about the size of the San Francisco peninsula." It stretched 1,500 feet down into the ocean, but the wind "pushed so hard on [the] … iceberg that it rotated around like the hour hand on a clock running backward."3
Great winds have their effects on the landscape too, not just on its inhabitants. I've seen the effects of aeolian erosion, which is what the geologists call sandblasting, in the Sahara Desert. Whole mountains have been stripped by the winds into grotesque castles, some of them with spires a thousand feet tall. Entire mountain chains heaved into being by tectonic shifting are reduced to dunes in the scouring winds. It's possible that the shape of the great pyramids of Egypt was inspired by natural erosion in the Western Desert. Geologist Farouk El-Baz has found that a pyramidal shape best resists erosion because it directs the wind smoothly upward, as does the prow of a boat, so natural pyramidal hills came to stand as a symbol of eternity. If the pyramids had been cubed, they would have disappeared millennia ago.4
Power and telephone companies in desert areas have to protect the lowest few feet of their wooden poles—the poles of the trans-Caspian phone lines lost half their diameter in a decade. On a tiny scale, I've seen a glass bottle carelessly discarded on the sand by a passing traveler turn opaque from the sandblasting in a day or two; in a month it too was dust and moved with the wind, dancing in little leaps, to disappear into the dunes. Wind is the most potent of all erosional agents, trumping even water. It carries away somewhere between 200 million and a billion tons of topsoil and sand from the Sahara and Sahel every year, most of it dumped at sea but some ending up in Europe or even North America. In the desiccated air of the Sahara, wind-blown abrasive sand beats on metal with a sound like heavy rain. It can rattle against legs and arms and face like hail, causing abrasions and drawing blood.
Owen Watkins, a surgeon traveling with Kitchener's army toward Khartoum, once saw a train engulfed by such a sandstorm. Maybe not quite as violent as the Wreckhouse winds of Newfoundland, but in his book With Kitchener's Army, he described it as "quite the most grandly awful sight, a great bank of dust about 100 feet high, stretching for miles and miles in front of us and rushing upon us with a dull roar … The [invalid convoy] train we had seen start had to pull back into the station, and another train a few miles out into the desert had to stop, being nearly swept off the line by the force of the wind. After that experience I find it easy to believe the stories, often read before in skeptical spirit, of whole caravans being lost and buried in the desert."
One such story, recounted with commentary by Herodotus in his Persian Wars, written about 450 B.C., told how Cambyses, the conqueror of Egypt in 525 B.C., dispatched an army to quell the stubbornly oppositionist Ammonites, keepers of the oracle at Jupiter Ammon, at Siwa in the Qattara Depression in the Egyptian Western Desert. "The men sent to attack the Ammonians, started from Thebes, having guides with them, and may be clearly traced as far as the [Kharga Oasis], seven days journey across the sand. Thenceforth nothing is to be heard of them, except what the Ammonians report, that the Persians set forth from the Oasis across the sand, and had reached about half way when, as they were in camp breaking their fast, a strong and violent south wind arose, bringing with it vast columns of swirling sand, which covered up the troops and caused them to disappear. Thus, according to the Ammonians, was the fate of this army." Forty thousand men, with their panoply and pay chests, with their animals and their food stores, with their armor and weaponry, with their commissary and their water skins, perished in the sand, their skeletons polished and preserved, perhaps, but never found.5
At sea the gales are terrifying even to experienced sailors; in the stormy winter of 2002 to 2003, a container ship, a vessel fully seven hundred feet long, limped into port at Halifax, wreckage still hanging over its gunwales; it had been caught in an Atlantic gale and had fifty containers torn from its deck and dashed into the sea.
Winds heap up the water into massive waves. Oceanographers say that it is possible—at least in theory—for waves of 220 feet to be generated in the deep ocean, about the height of a twenty-story building. That no one has ever reported such a wave doesn't mean they haven't occasionally occurred; after all, hundreds of thousands of ships have vanished since men began venturing onto the sea, five thousand or so years ago. Slightly smaller but still gigantic waves, however, are encountered too often for comfort. Hurricane Ivan itself churned up huge waves as it passed through the Gulf of Mexico, reaching as high as forty meters, or 131 feet, something that was explained in a paper by Peter Bowyer and Allan MacAfee published in June 2005 in the Journal of the American Meteorological Society. Ten years earlier, in September 1995, the luxury liner Queen Elizabeth 2 was on route from Cherbourg to New York, and had to change course to avoid Hurricane Luis. Nevertheless, the vessel encountered a series of seas 60 feet tall, with occasional taller crests. At four in the morning—mercifully after even the most persistent revelers had retired for the night—the Grand Lounge windows, 72 feet above the water, were smashed by a breaking wave. Ten minutes later, the bridge crew saw a wave dead ahead that looked, they reported later before the publicity-spooked owners told them to zip it, as though they were heading straight for the white cliffs of Dover. The wave seemed to take ages to arrive, but it was probably less than a minute before it broke over the bow. A second wave, immediately behind the first, crashed over the foredeck, carrying away the forward whistle mast. The captain, R. W Warwick, admitted in a report later that it can be difficult to gauge the height of a wave from a vessel, but declared that the crest was more or less level with the line of sight for those on the bridge, about 95 feet above the surface. The officers declared that it was not a swell but a true wave; and Canadian weather buoy number 44141 moored in the area recorded a maximum wave height of 98 feet at that time.6
High-latitude waves tend to be bigger and more ferocious than tropical ones, because cold air, which is denser and heavier, can raise higher seas at a set speed than warm air can.7 Around Cape Horn, the winds lift the waves to awesome heights. Francis Drake's nephew, who was with his eminent uncle on one of his voyages, described "the seas, which by nature are of themselves heavy, and of a weigh tie substance [were] rowled up from the depths, even from the roots of the rocks … exceeding the tops of high and loftie mountains."8
Where ocean and shore intersect, so-called storm surges are caused in high winds. Much of the damage done by hurricanes is not through the wind itself but by surge-related flooding. I know this from my own property. When Hurricane Juan hit Halifax in 2003, it did massive damage to that relatively unprepared city. A mere hundred miles away at our house the winds were only a gale, but the ocean reared up like a beast, tearing at the shoreline. It thundered over our protective rocky beach and tore up our boardwalk, hurling it into the forest a full hundred yards away; the breakers were thirty-five feet tall, the storm surge almost eight feet, and the tide was high, another six feet or so … We get winter storms pretty well every year with hurricane-strength winds, but they seldom cause storm surges. One reason is that North Atlantic winter storms are bigger than most hurricanes—not in intensity, but in sheer spread. Their effects are therefore more diffused. The analogy is that a man with size-thirteen shoes leaves a shallower imprint in the ground than a woman with stiletto heels, which dig deep into soft earth. Snowshoes have the same spreading effect.9
The meteorologist's definition of a storm surge is "a complex deformation of the sea surface induced by the cyclonic winds on coastal waters, which surge as a sudden tide against the coast. The level of the sea can be raised by up to 10 feet for several hours. Depending on the characteristics and relative positions of the cyclone and the coast, the level of the sea can go up a further 3 feet by the low pressure."10
For many years scientists believed that the reduced atmospheric pressure alone could account for surges. But most of it is really wind-caused. A 35 millibar decline in pressure will raise the sea surface no more than a foot, and pressure-related surges seldom exceed three feet. By contrast, the storm that rolled through Galveston in 1900 raised the water level over fifteen feet; and Hurricane Camille raised the waters of the Gulf more than 25 feet.n11
Even lakes can be affected. The Great Lakes of course, but one of the worst surges in memory was when Lake Okeechobee in Florida surged eighteen feet in 1926, drowning almost two thousand people. In the 1950s in Russia, Lake Baikal, the largest lake in the world in terms of volume, reared up in a storm surge and carried away an entire lumber mill.
On a greater scale still, as already noted, winds affect the oceans themselves. The great ocean currents, the earth's temperature regulators, are themselves caused by winds. Winds exert stress on the surface of the seas, and set entire oceans slowly spinning.
II
The critical thing to remember about wind is that the force it exerts doesn't just double when the wind speed doubles—if that were so, hurricanes would seldom cause any real damage, and on the other hand, windmills would only work in major gales. In fact, the inertial force of wind, the direct push of wind against an object, or the force exerted when something stops or changes the direction of moving air, is proportional to the wind speed squared.
A wind of 20 miles an hour will exert one pound of inertial force on a flat object 1 foot square. But this doesn't mean that the pressure will double if the wind doubles—that a 40-mile-an-hour wind will exert only two pounds of pressure instead of one. Instead, every doubling of the wind speed quadruples the inertial force, and a wind three times as fast exerts a force nine times as severe. You can see how rapidly this escalates if you take, say, the wall of a small shed some 400 feet square. It will face 400 pounds of pressure in a 20-mile-an-hour wind, 1600 pounds in a 40-mile-an-hour wind, 6,400 pounds in an 80-mile-an-hour wind and an astounding 14,400 pounds, more than 7 tons, in a 120-mile-an-hour hurricane. A building will have to be twice as strong to survive a 120-mile-an-hour wind as it would an 80-mile-an-hour wind. (See Appendix 11 for a wind force table.)
The effect is exaggerated by the so-called blast effect of a gust. In the case of a building, if a window or door suddenly breaks open in a gust, wind will explode into the building and destroy it from the inside. "No realistic amount of structural engineering can safeguard a building against the blast effect. It makes much more sense to take every possible precaution to ensure that windows and doors will not break or fly open during high winds."12 But sealing the house tight against the wind may not be the right approach either. It may make more sense to enable some kind of controlled air flow through a building during a major storm. One homeowner whose house survived a major hurricane in Florida had closed his doors and windows tight and even sealed two turbine vents in the attic. The house was doing well until an errant tile smashed a window, and the wind immediately started to inflate the house like a balloon. He was saved only because the plugs in the turbine vents blew out before the walls did, and the pressure dropped at once.
Aerodynamics have shown that winds will exert an upward lift on any roof pitched less than 30 degrees, an outward force on walls parallel to the windstream, and a drag force on walls and gable slopes facing downwind. "In any major windstorm, then, some parts of a building will be pushed inward while other parts are being pulled outward. This combination of pushing in one place while pulling in another is particularly abusive and leads directly to many structural failures. Moreover, as wind direction shifts, and it usually does during any major storm, many of the forces reverse direction. Often a building will be weakened during the first half of a hurricane, then will collapse when the winds reverse their direction after the eye passes through."13
Interestingly, the pagoda style of roof design generates what wind-tunnel experts call a negative lift where they overhang, helping to keep the roof in place in typhoons. Which may explain why so many pagodas have survived for so long in typhoon-prone parts of the world.
A survey of Dade County, Florida, homeowners after Hurricane Andrew had passed by found that many of them had taken refuge in a bathroom or closet in the middle of a house. Such spaces, however, provided little more than emotional cover in a storm that was known to have driven two-by-fours through concrete walls. Much of Florida was considering adopting a code that would require new houses to have at least one room thought to be projectile-proof. Under consideration was an eight-foot-square room sheathed in two-by-four studs covered with four inches of plywood.14
Because hurricane winds increase sharply only small distances above the surface, what happens to high-rise buildings in high winds? Their steel skeletons can almost always stand the strain—though even the idea of being inside a high-rise that can sway more than twenty feet in a hurricane would make anyone queasy—but the winds could easily tear away the cladding and the curtain walls. The best-known instance was Hurricane Hugo in 1989, whose 135-mile-an-hour winds flattened thirty major downtown buildings in Charleston and ripped off the outside walls of waterfront condominiums. Tenants in a fifteenth-floor apartment said afterward they'd gotten out just as the outside walls went, sucking out all the furniture.15
Some of the most powerful winds, curiously, come directly downward— not just in tornadoes, but in so-called downbursts associated with thunderstorms. In fact, more damage is done by downbursts than any other kind of winds, perhaps because they are more frequent—a recent study found that more than two thirds of all high-intensity winds that did damage to buildings and structures came during thunderstorms. 16 Unlike hurricanes, the worst effects on downbursts are close to the ground, and so affect low-rise buildings more than high-rises. Construction engineers and wind tunnel experts have been testing novel geometries and odd-looking protrusions on low-rises to reduce the wind-induced uplift of roofs. They include leading-edge spoilers, porous fences at building corners, similarly porous parapets, and roof-edge circular cylinders to induce downward flowing vortexes to counteract lift. In 2001, two researchers were granted a U.S.
patent for "visually subtle spoilers … to achieve a reduction in peak negative pressures along the roof leading edge of low-rise buildings." Other research has shown that the best building to withstand high winds is a brick home with perimeter wall, roof, and balcony alignments all designed to provide the wind with a path of least resistance. Still, an experimental home built with precisely those factors in mind blew apart during Cyclone Tracy in Darwin, Australia, in 1974, along with half of the city. The cause—inadequate component fasteners. The building was a good idea; the attention to detail not good enough; the result complete failure.17
III
We now know what hurricanes and their typhoon cousins are. We know where they start, and some of the hows and whens, and all this knowledge is useful. We don't know much about the whys, though. Nor is it likely that we will ever be able to control hurricanes, though that hasn't stopped people from trying.
The first clues to the hows and whens of hurricane formation lie in the wheres—where they start and, more interestingly, where they don't. Hurricanes never start on the equator, for example— there is no Coriolis force at the equator, and so no way to get a storm spinning. They always start in latitudes just high enough for the Coriolis force to be appreciable. But they never start at high latitudes either—the ocean is too cool there, the sea surface temperatures, or SSTs, as the hurricane hunters call them, far too low. They may have their remote origins over land, especially where high heat and cool air produce thunder cells, but hurricanes proper never form on land—evaporated moisture is their fuel. Hurricanes hardly ever form in the southern Atlantic either—before they can properly organize they are broken up by the prevailing westerlies, which in the southern hemisphere are much closer to the equator, although in 2004, for the first time, Hurricane Catarina struck Brazil, the extraordinary product of high sea-surface temperatures, low vertical wind shear, and strong mid-to-low-level blocking currents. Few tropical cyclones start in the smaller Indian Ocean. Or if they do, they don't amount to much—the "fetch" of the ocean, the amount of sea available for a storm's nourishment as it travels, is too small.
Many of the Atlantic storms, like Ivan for example, are born in the Sahara, as the superheated air of the desert meets the cooler air over the mountains, and then is energized as it drifts out into the Atlantic—and so the weather offices in Timbuktu and Niamey and in Abidjan, in the Cote d'lvoire and Dakar, in Senegal, are the early-warning systems for Atlantic hurricanes. Early-summer Caribbean hurricanes, though still made up of African-born tropical waves, tend to form in the western Atlantic and in Caribbean waters, because the sea there is shallower, and heats up faster. It is the mid-season hurricanes that pass over the Cape Verde Islands before heading their relentless way westward.
In the eastern Pacific, most hurricanes fizzle harmlessly in the colder water west of the Americas. Hawaii gets a few, but the prevailing easterlies steer most of them well south of the islands. The north and western Pacific is even more prone to cyclones than the Caribbean, and the "season" is yearlong and therefore much more dangerous than the six months or so of the Atlantic. Pacific typhoons are born at sea, and tend to be larger and better organized than their Atlantic cousins—the much greater stretch of the Pacific gives them substantially more room to mature than the smaller Atlantic. The classical Japanese description of a typhoon is kamikaze, or "divine wind"; Japan and the Philippines are frequently assaulted by three or more storms a year—Japan had ten in 2004. Korea, China, and Vietnam are also vulnerable. To the south, Australia's northern littoral is under threat from typhoons in summer and fall, from December through about May; about a dozen cyclones a year form offshore, and some of them strike land. The worst storm in Australian history was Tracy, which struck Darwin on Christmas Day 1974. New Zealand's waters are too cool for tropical cyclones, but like Maritime Canada the islands are prone to strong extratropical frontal storms as the cyclones wind down.18 Pacific typhoons are tracked by storm centers in many places around the ocean's rim, but the most active are the Typhoon Center in Tokyo and a facility run by the U.S. Navy in Pearl Harbor, Hawaii. One of the oldest weather offices in the world was set up by the British in Hong Kong in 1884; the Chinese are still using it to track typhoons.
A precondition for the transformation of a line of thunder cells or a low-pressure wave into a tropical cyclone is stable air, a local environment where the winds don't change very much. Hurricanes don't form in patches of turbulent or active air—powerful as they are, destructive as they are, they are also curiously vulnerable at birth. There must be very little wind shear, allowing the big cumulus thunderstorms to build vertically. Any strong wind above a hurricane will destroy it, either by tipping it over through shear, or by literally poking holes in the warm core tube, allowing the warm air to vent, which weakens it. Or they'll "plug the chimney" at the top, where the storm's vent is.
Another precondition is warm water. The ocean below must be at least 260 Celsius, but preferably 26.50 or higher. No real scientific consensus exists on why this number is the magic one. It has perhaps to do with the climatological factors governing tropical oceans, but which factors and precisely how are still unknowns. Temperatures can be higher than 26°, but not lower—the higher they are, the greater the potential for damaging convection currents to occur. Higher temperatures don't increase the probability that a system will coalesce into a hurricane, but they do tend to make that hurricane more intense.
If these preconditions are met, the winds of the passing thunderstorms, still just a tropical disturbance or tropical wave, will evaporate this warm water, and because of the Coriolis force, the winds will lazily circle inward to the center. This causes a small vacuum, and the pressure drops, driving the warm, moist air upward. At about 2.4 miles above the surface, the vapor begins to condense into water, or into shards of ice and wet snow, and the act of condensation causes something deadly to happen: The heat, and therefore the latent energy contained in the moist air, is released. This energy is substantial—a kilogram of water will release enough energy to boil half a liter of water. This liberated energy then reheats the air, driving it still further upward, creating even lower pressure below, and drawing still more warm, moist air into the atmosphere. Consequently, the pressure drops still further, more heat rises into the sky, and the system, now beginning to spin faster, becomes a self-sustaining storm, isolated from the airstreams that surround it. If it remains coherent and well organized for at least twenty-four hours, that's when the hurricane centers of the world start to pay attention, because the precursor conditions for tropical cyclone formation have been met. If the sustained winds reach 23 miles an hour, the system is declared a tropical depression. Then it is given a number. Tropical depressions are tracked, because they are embryo hurricanes.
These tropical depressions are already convection engines, their fuel provided by the warm sea water, which evaporates ever faster in the higher winds, causing ever lower pressures. After a few days, the tropical depression may escalate into a tropical storm. If the sustained winds reach 38 miles an hour, the meteorologists reach for their naming dictionaries and give the new storm a moniker.
The practice of giving storms names rather than geographic locator numbers began in the final years of the nineteenth century in Australia, where forecaster Clement Wragge cheekily gave destructive typhoons the names of women he knew (or wanted to know), or politicians he thought were idiots. Bob Sheets, former director of the National Hurricane Center, credits a 1941 novel called Storm, by George R. Stewart, for bringing the practice to the Atlantic. Sheets notes: "It was easier, the hero said, to say 'Antonia,' rather than 'the low pressure center which was yesterday in latitude 155 E, longitude 42 N.' "19 In World War II, military forecasters helped pilots to keep various systems separate with names rather than coordinates; the assigned names were random but always female, generally the names of wives, girlfriends, or, like Clement Wragge before them, women the forecasters hoped would be girlfriends. It wasn't until the 1970s that the practice was systematized. At that time forecaster Gil Clark drew up a list of women's names from baby-naming books and his own family. Men's names were added by the fiat of the World Meteorological Organization, under pressure from an indignant woman's movement, in 1978. Bob, a curiously boyish name for a major force of destruction, is the first male hurricane on record.20 Gilbert, Clark's own given name, by coincidence still holds the record for the most intense Atlantic storm on record, with a low pressure recorded at 888 millibars. The world-record low pressure is 870 millibars measured in Guam in 1979.
At 74 miles an hour, when a tropical storm becomes a baby hurricane, pressure can drop very rapidly from the periphery to the center—pressure has been tracked to drop 38 millibars in thirty minutes in particularly severe storms. The energy is enormous—even a moderate hurricane releases enough energy in a single day to equal four hundred 20-megaton nuclear bombs; if converted to electricity, it would be enough to power all of New England for a decade, with enough left over to run toasters all over the Canadian Maritimes.
Meanwhile, the whole system is moving—for both Atlantic hurricanes and Pacific typhoons, generally westward at first, then curving northward and eventually northeast. This is why, in the northern hemisphere, winds are strongest to the storm's right, where the directional speed of the storm's travel is added to its rotational speed. To its left, the forward speed mitigates the observed wind speed. The faster the storm is going the more exaggerated this effect. If a hurricane is going to hit, you should hope you're to its left.
When a small hurricane's convection pattern strengthens, the centripetal wind flow gains speed, the input of warm moist air continues to escalate, even more large-scale condensation occurs during the ascent, and enormous amounts of latent energy are released, which in turn result in stronger winds, which in turn lead to uplift of more warm, moist air to condense and release ever more energy … A mature hurricane never blows itself out, as long as there is warm water to sustain it.
The evolution from depression to full-blown hurricane usually takes a good four days. It took Ivan not quite three.
It is curious that with all this data available, and with so much attention being paid to hurricane tracks and intensities, that the actual birth of a hurricane still remains invisible. As I've said, we know where, we know when, and we know the necessary preconditions—but we still don't know why. What is the tipping point? What makes one system coalesce into a storm, another to dissipate? After all, a hundred Saharan thunderstorm systems drift into the Atlantic each year, but only a fraction even become tropical disturbances. Of those that do, only a fraction become storms, and not all of those become hurricanes. Globally, tropical cyclones are still uncommon. In any given year, the number will vary from thirty to one hundred, with somewhere around ten or twelve in the western Atlantic; of those, perhaps three or four will be defined as major. This may be changing: From 1951 to 2000, there was an average of ten named storms in the Atlantic each year; in the past few years the number has increased to about fifteen, and may still be going up—there are more tropical depressions to start with, and the ocean is two to three degrees warmer than in earlier decades. But the moment a storm becomes a hurricane is still hard to see.
No matter how closely scientists monitor the data, the exact instant eludes them. Only in what meteorologists call hindcasting, the after-the-fact scrutiny of the data, can they approximate it. The first hint is when they see wispy clouds lazily circling, drifting inward toward a point, an early sign of a system's struggle to overcome entropy, a sign of what they call, for obvious reasons, "organization"—a "well-organized storm" is a storm with serious potential. But even then, the why is mysterious. Storms are caused by dozens, perhaps hundreds, of forces that intersect and interact, sometimes directly, sometimes in ways so subtle they are hard to detect by even the most cunning of models. They have, in the scientific jargon, "a sensitive dependence on initial conditions." They are nonlinear, which mostly seems to mean they don't behave at all predictably.
In theory, it should be easy to track the beginning of a hurricane: Simply wind the film backward. We already know how its effects on the American coast (Step C) result from its westerly track across the Atlantic (Step B), which was caused by a tropical storm off the Sahara (Step A). Why not then follow it backward from C to B to A and then beyond to see how the whole thing began? With the vast array of data provided by the globe-encircling network of satellites, we seem to have plenty of information—those satellites can track phenomena to a resolution of a few yards. In practice, what you see when the film is unspooled is this: hurricane, smaller hurricane, tropical storm, tropical depression, thunderstorm, moist windy spot, then a set of weather conditions that in no way look any different from those that cause, well, nothing … What is it that energizes some of these warm moist spots into hurricanes? No one knows. All they can say for sure is that it must be very small, because it is presently beyond our ability to track.
Ernest Zebrowski Jr. in Perils of a Restless Planet explains how computer simulations of hurricanes, while crude, go some way to illustrating the phenomenon. A storm is created on screen using hypothetical initial data. Columns of numbers then yield wind speed, storm speed, barometric pressure, temperature, and other measurable variables. By itself, such a simulation yields no information of any value. But if you then conduct a second computer run, then a third and a fourth and a hundredth, giving each one a tiny variation in the initial data—say a few millionths of a degree difference in temperature, much too small to actually measure, or a tiny variation in wind speed—something surprising happens. For the first few hours of the simulated run, the "new storm" replicates exactly the course and intensity of the old one. But then, the behaviors of the two virtual storms begin to diverge, and eventually they differ quite radically—one might veer sharply north, the other continue on its westward course; one may die, the other bear down on Florida. Some theories suggest—though still unproven—that something as small as the effect of a flock of birds flying into the originating "warm moist spot" may end up changing a storm's history. Or perhaps the storm simply falls over in a light breeze. Or the low-pressure system may pass over a tiny atoll or island and be thoroughly changed in its nature. The errant butterfly of ecological legend may not be enough to change a storm's course, but if an embryo disturbance passes over a single resort hotel, that might well be enough.21
A scientist at MIT, Edward Lorenz, independently discovered the same phenomenon when he did the same storm-modeling run on two different computers, the old one using data to three decimal places, the new one to six. His model storm, too, produced major deviances after setting off similarly—a relatively tiny change, from 3.461 in the first run to 3.461154 in the second, produced large differences in both the storm's intensity and its predicted path. It was Lorenz who called the phenomenon "sensitive dependence on initial conditions," now more popularly known as chaos theory22
Will we ever be able to achieve absolute accuracy in storm forecasting? Only, says Chris Fogarty of the Canadian Hurricane Centre in Dartmouth, if we have data inputs every few inches across the planet, both vertically and horizontally, something that is clearly impossible. With that many sensors, there'd be no room for people. And even if we were to blanket the earth with a sensor for every molecule, what then? The atmosphere contains more molecules than there would be electrons in any computer, so the calculations would end up being slower than the reality they were forecasting— you'd have a forecast that arrived after the event being predicted.23
The charts of historic hurricane tracks pinned to bulletin boards in hurricane centers everywhere need to be interpreted with great caution. Both the tracks and their numbers are truly unpredictable, classically chaotic. To speak of "increasing numbers of severe storms," or of "the storm of the century," or to predict the numbers that will occur in any one year is, in Zebrowski's phrase, to "entertain a statistical delusion." Because hurricanes, like other natural forces, are chaotic systems, you cannot predict how many will happen by looking at what happened in the past. There may be apparent patterns, but they are illusions. So if you know that from 1951 to 2000 the average annual number of named tropical storms was ten, six of which became hurricanes, or if you know that last year there were fifteen named storms and nine hurricanes, this average and this raw number are entirely useless to predict what will happen this year, or next.
IV
So great is the appetite for data about hurricanes that pilots have been flying into their deadly vortexes for more than sixty years, breaking through the maelstrom of the eyewall into the calm center of the eye itself, a beautiful and terrible place. They did this at first because they were told to (they were, at the time, military pilots in a wartime situation) and partly because the pilot's code of permanent insouciance meant that the challenge was irresistible. It was no surprise, then, that the pilots who did so referred to their flights as penetrations, and to the storms as females—the practice of assigning storms female names had started only a few years earlier.
The first deliberate penetration into an eye was in the summer of 1943. The pilot was Joseph Duckworth, at the time a flight instructor and a specialist in instrument flying, as opposed to visual flight rules. Part of his intention was to put to an extreme test his theories about flying correctly without, essentially, seeing anything outside the plane. Neither Duckworth nor his copilot, Ralph O'Hair, troubled themselves with keeping notes; apparently, undergoing the experience was justification enough. Still, they did confirm one of the existing theories about hurricanes, which helped confirm, in turn, notions of how storms persisted. They showed that temperatures inside a storm, in the eye, were twenty degrees warmer than outside it at the same altitude.24
The weather data these flights provided were useful, so useful that when the war ended, the military kept up its mission of weather reconnaissance flights. The most important squadrons were 57th Weather Recon based at Hicken Air Force Base in Hawaii, and the 53rd Weather Recon of the Air Force Reserve in Biloxi, Mississippi. The 53rd still exists, now part of the 403rd Wing, based at Kessler Air Force Base in Biloxi; they're called the Hurricane Hunters, and use ten Lockheed-Martin WC-130 aircraft. Other squadrons flew missions at Guam, Alaska, and Bermuda.
In the 1950s, Max (Maximillian C.) Kozak was chief warrant officer for the 57th. He was also a meteorologist, and after he left the Air Force found a home at the weather station at the Franklin Institute, in Philadelphia. His first time into a hurricane, as he recalls it, was a mission that ended at Johnson Island in the summer of 1955, through the eye of Hurricane Dot. He was the weatherman part of the crew of ten, stationed in the back of the B-29 bomber of wartime vintage, then the weather platform of choice, with his instrumentation and his single dropsonde. The briefing was to supplement whatever the ground stations already knew, to fill in the gaps in their knowledge of upper air storm data.
"Our mission was to fly daily," he recalls, "on general reconnaissance missions, mostly descending from 18,000 feet to identify surface craft in the area." Hurricane reporting was a sideline. Dot was their opportunity.
"Our crew was scheduled for takeoff at midnight. Dot was just off the big island of Hawaii. Light rain was falling as we took off and climbed to 18,280 feet. The idea was to 'box' the storm, collecting data from its periphery outside the 50-mile-an-hour wind band, and to penetrate the storm—meaning penetrate the wall cloud into the eye—at sunrise. The first go-around was no problem, but on the second go-around the navigator spotted something on the radar. He called me over. I got out of my seat and saw a saberlike line of activity moving with the winds northward. I knew what it was.
"I said to the pilot, 'Can we go around this?'
"But the tail of the anomaly extended eastward, around 50 miles or so, so the pilot said, 'No way. There are rocks in those clouds.' We'd be over land. The rocks were the mountains on Big Island.
"But I knew what we were heading for, so I said, brace up, we're going to hit a down draft. Everyone strapped in, and we just waited. For ten minutes we flew horizontally, normally. Then, sure enough, down we dropped, suddenly, a thousand, three thousand feet in just seconds … I thought for sure the wings had been pulled off and looked out the window to see … and there they still were. As I looked, I saw a sort of undulation upward. Somehow, we got a boost of wind from below and climbed out."
Max recalls that the second navigator, a hurricane virgin, didn't take the drop so well. "He began to shout and yell, and as we called it 'fell out of the tree.' We had to subdue him, so we tied him up and put him under the navigation table where he fell asleep."
The flight continued to box the storm as it moved steadily northwestward. No one made notes. They couldn't. The turbulence was too severe. No more heart-stopping thousand-foot drops, no more freaking fits for the second navigator, but the plane was shaking like an old man with the ague and it was impossible to do more than cling to the nearest stanchion and just watch as the pilot wrestled with the controls.
"Finally, and almost instantly, we just popped out into the eye, into the most beautiful sight. It reminded me of the Vatican, the semicircle of marble columns around the plaza before St. Peter's, but these columns extended all the way around, 360 degrees, and the convection currents had pushed them 50,000 feet into the sky. It was exquisite. The columns, the updrafts that came with the surrounding thunderstorm activity, formed a perfect circle. Winds were minimal in the eye, almost nonexistent. I remember sunlight coming in across the eye. Sometimes eyes are covered with layered cloud, but not with Dot. You could look straight down from the airplane to the ocean, 18,000 feet below. We could see the churning, the white caps on the sea."
Over the centuries, many have seen the eye of a hurricane and survived to tell of it, though generally from the bottom looking up. Sailors have reported stars at night, pristine blue skies by day. The air is reported to be luminous, with an unearthly gleam, with colors in a demented palette of lurid blues tinged with violet and somber greens. Winds can be utterly calm—unlike the water, which is churned by the surrounding and conflicting winds into raging and directionless mountains. Not all storms have eyes. Some that do are shaped like massive replicas of the old Roman Coliseum, sloping in from the top, perfectly round, as though they were forming seating for the gods, waiting for a gladiatorial combat of giants to begin below.
The sound in the eye is deep and ominous, like a freight train passing inches overhead, numbing the brain.
Max and his fellows kept their course, banked left. "We had to locate the center so we drew a line across, I watched the radar altimeter and marked the location of the lowest pressure, then cut back along a left turn. There was not much wind, only a slight descending motion. We measured our drift with a drift meter, our best way then of measuring wind speeds. As we made a ninety-degree turn, we released the dropsonde."
The adventure of Dot wasn't quite over. "We completed the mission and headed home. On the radio we heard that we couldn't land because there was a foot of water on the runway in Hawaii. The nearest alternate runway was Johnson Island, roughly 1,200 miles southwest from where we were. The navigator took a look at the distance, the course, and the fuel reserves, and said to me, 'We need some winds, to get us home.' I took the last maps I had, which were six hours old, and tried to put together a picture of what the wind pattern would be. I gave my winds to the navigator, and he sent them to the engineer. His job was to take my wind and convert it into 'fuel.' According to my calculations, we would be able to see Johnson Island just about the time the tanks emptied. On his own, the pilot decided to descend to see if he could find more favorable winds near the surface. We went down, to no more than two thousand or three thousand feet, and flew at this altitude for several hours.
"As I had predicted, just as we saw the lights on Johnson Island, the engineer announced that we were empty We couldn't go around into the wind—no time. The pilot took a downwind leg and landed the plane, then reversed all four engines. We skidded the length of the runway."
After the plane stopped and the crew got out, Max took a look at the wings. Rivets had popped out all down their length.
Max penetrated six hurricanes in his time with the Air Force, between 1953 and 1958. Of all his reconnaissance flights, the most disturbing wind he experienced was not natural but manmade—he and his crew were assigned to fly into the mushroom cloud of a nuclear explosion. Why would they do this? "To see what it is like in there …" This was the 1950s. Radiation was known, but its larcenous carcinogenic qualities were not appreciated—scientists still regularly stood unprotected in the Nevada desert to watch the mushrooms ascending into the sky.
Max won't talk about the specifics of the mission—it was classified then, and still is. What he will say is this: The mission was to take readings inside the stem of the mushroom at 18,000 feet. Max was the radiological officer. "After detonation we went into the stem. It was the most beautiful thing I have ever seen, I saw shades of blacks, reds, pinks, and purples, colors that I never saw, ever again. The temperature was hot in the stem. We flew at 18,000 feet, took our readings, and came out on the other side looking like a flocked Christmas tree. We were 'hot' with radiation, but that wasn't the worst of it. The coral from the ocean floor, close to where the bomb had exploded, had been vaporized, and it crystallized on the plane as we flew through. It was a huge problem, bigger than the radiation. It made the plane too heavy. We were going down. I told the pilot to head for the rainstorm showing on the radar to attempt to wash off the weight of the coral. We did. And we landed safely, thankfully. But that plane was toast. It never flew again."25
One other recon flight flew into a hurricane in the 1950s that had picked up radiation from a nearby nuclear experiment. All that the crew were told afterward was to take a long shower.26
In fact, the danger posed to aircraft through flying into hurricanes is generally not substantial. This is because most of the wind in a hurricane is horizontal, and planes simply become part of the flow, just as they do when they hop a jet stream on their way across the Atlantic. It is the downdrafts that are the problem, and they are much more likely in thunderstorms than in hurricanes. Thunderstorms don't spin. They are an instability in the atmosphere that causes rapid overturning of air, and very rapid ascents and descents. But downdrafts are not unknown in hurricanes, which do spawn both tornadoes and thunderstorms—Max hit a downdraft on the periphery of Dot, and planes have, indeed, been known to drop a thousand feet in a few seconds inside hurricanes, just as Max described. But in thunderstorms such downdrafts are much more common, which is why pilots take a good deal of trouble to avoid such storms when they can. Most experienced travelers can report at least one such downdraft. My own score is two—one over the Congo, when my Zimbabwe-bound plane faced a wall of thunder cells it couldn't evade, and another on a flight to Tel Aviv, during which the coffee wagon and its flight attendant actually hit the ceiling, damaging both and causing panic among the passengers, most of whom (considering the destination) thought for a frightful second that a bomb had gone off.
That downdrafts don't happen very often in hurricanes doesn't detract from the bravery of the early pilots, who really didn't know what to expect, in terms of turbulence, or wind speed, or indeed rainfall.
Chris Fogarty, who has flown into several hurricanes in the Canadian Hurricane Centre's Convair 580 turboprops, says it is mostly experienced as light chop, "like driving a car along a pot-holed road." Hurricane Michael in 2000 was somewhat turbulent along its east side, and Juan, of 2002, pushed the aircraft around a bit. "There were times when my stomach felt it was still a couple of hundred feet below." His worst experience was trying to land in the aftermath of the flight into Tropical Storm Karen, when a low-level wind abruptly blew the plane several hundred feet sideways just above the runway; they had to abort and were diverted to Quebec City, more than six hundred miles away.27
When a U.S. Hurricane Hunter plane flew into Hurricane Hugo in 1989, it too encountered unexpected turbulence. Peter Black, of the National Hurricane Center's research division, recounted that "when we got there the winds were over 200 knots and we just about lost the airplane. It was a really rough ride. An engine caught fire. I have a vivid recollection of seeing the flames shooting by my window. The turbulence was so severe that the fuel regulator had malfunctioned. They were able to douse the fire right away and feather the engine, but that meant we were in the worst part of the storm with only three engines."
Still, it was all for the best in the worst of all possible turbulences, as Black confesses: "In retrospect [we turned up a] really unique set of data. They showed for the first time what these smaller-scale meso-vortexes [little tornadoes drifting around the spinning eye-wall] look like that were contributing to the storm's deepening. We still don't know what role they play exactly. But we were able to identify that as a new entity, a new scale of motion in a hurricane vortex that we had never really documented before."28
The military, or at least the Air Force Reserve, still operates Recon 53, the Hurricane Hunters, but most reconnaissance monitoring has been turned over to the Hurricane Research Program within the weather bureau. Most flights are now arranged through NOAA's Aircraft Operations Center, based in MacDill Air Force Base in Florida, which tracks hurricanes, monitors air quality, surveys whale populations, measures snow cover, and performs many other tasks.29
In the 1950s, the same decade that his military and political masters blithely sent Max Kozak into the heart of a nuclear fireball, anything seemed possible to science. If they could tame the atom, why, hurricanes and tornadoes should be a snap. Weather control, the notion of bringing planetary weather under the benign direction of the disinterested, politically neutral weather bureau, was in the air, so to speak, a refugee from the hoariest tales of science fiction. In the old days, rainmakers did dances and made incantations and sacrificed fowl or lambs or, occasionally, their virgin daughters, to the weather gods to make things happen. Modern science was beyond that. You should only have to understand what makes the great storms tick to know how to make the ticking stop.
A sample of this thinking is from Irving Langmuir, a meteorologist who headed a cloud-seeding project known as Project Cirrus: "We need to know enormously more than we do at present about hurricanes … [but] I think that, with increased knowledge, we should be able to abolish the evil effects of these hurricanes."30 Amateurs enthusiastically joined in the hunt for the magic technology that would do the trick, and more or less loony suggestions ranged from firing artillery through their tops to disrupt the rotation, to using giant fans to divert them, to flying hundreds of propeller aircraft against their rotation to unwind them, a device used to good effect by Superman in one of the Christopher Reeves movies to unwind time. Perhaps you could cool the ocean by towing into place massive Antarctic icebergs? Or by laying a cooling filament on the ocean surface? In Max Kozak's time, plans were mooted to see if a hurricane could be blown apart by a nuclear explosion; before it could be tested, wiser heads prevailed, suggesting that the added heat might actually intensify a hurricane, and in any case, what about the dispersal of the consequent radiation?
The notion of cloud-seeding, though, persisted well into the 1960s. It had been proposed as early as 1947, when scientists working on problems associated with aircraft de-icing found, for example, that moisture could be bled from clouds by a number of chemical reactions. Frozen CO2, popularly known as dry ice, could turn water and ice into snow; silver iodide, for its part, could precipitate out supercooled droplets and cause rain. Both chemicals would have the effect of cooling down the furiously hot core of the hurricane, and perhaps calm it down. In the last few years of the 1940s, military planes ferried Project Cirrus scientists into the eyes of several storms, including one hurricane where they emptied canisters of silver iodide. To their delight, the hurricane began to disintegrate—but twelve hours later had reorganized and reenergized again. Worse, it had taken a sharp turn to the west, and ended up pounding Savannah, Georgia—the notion that they may have actually caused the turn made the Project Cirrus people blanch, even though they were assured it was a midlatitude ridge of high pressure that had really done the trick.
By the 1960s the National Hurricane Research Center understood more about hurricanes and how very powerful they really were. And how very big—masses of air and zones of high and low pressure reaching to 40,000 feet and stretching over thousands of miles. Still, Congress allocated $30 million to further the research, so further it they did, creating Project Stormfury to see if they could, once again, use technology to fatally disrupt a major storm. Two hurricanes were seeded with silver iodide, and indeed, maximum sustained winds dropped, if only for a brief period, by some 20 miles an hour, a not-insignificant result. It was tried again in 1969 with Hurricane Debbie. When the results were tabulated, seeding was seen to have some short-term, very short-lived, effects, but had exerted no real pressure and caused no real damage to the storm.
The extensive press coverage of the time persuaded both Cuba and Mexico that the United States was using weather-modification techniques as a form of ecological state terrorism; both countries demanded that the experiments cease forthwith. Soon afterward they did cease, though less because Mr. Castro demanded it than because the results didn't seem justified by the effort expended. But in the end the experiments were worthwhile. Much data was collected. Forecasters knew more. Hurricanes were better understood.31
Science still hasn't quite given up the idea of controlling the weather. An MIT scientist has bruited the equivalent of setting small controlled fires to stop major forest fires—in this case starting small tropical cyclones to head off larger ones by cooling the ocean and thus robbing hurricanes of their energy source. His unlikely scheme, presented to a weather-modification symposium early in 2005, involves a chain of offshore barges loaded with a series of upward facing jet engines. Each barge would create an updraft, causing water to evaporate from the ocean's surface and thus lowering its temperature. The resulting ministorms should dissipate harmlessly. The scientist Moshe Alamaro blithely put the cost at a billion or so a year. Also among the optimists is Ross Hoffman, a scientist at a company called Atmospheric and Environmental Research in Lexington, Massachusetts, who has been given a $575,000 grant from NASA's Institute for Advanced Concepts to look into the possibilities. Along with a number of other environmental scientists, Hoffman has been using Lorenz's discovery, but the other way around—not to see how far a storm would veer with minute changes in input data, but to see what input data would be needed to push a storm off course. Hoffman asserts that he has twice successfully "steered" storms, at least on his computer.32
Hurricanes are chaotic systems. But chaos doesn't necessarily mean what its commonsense definition implies—chaos has rules of its own. Chaos theory contains arcana such as strange attractors, which are only strange in that they cannot be analytically computed, though they are physically real, and can be readily observed. They are called attractors because "chaotic systems never wander aimlessly through the universe; they always hover around one of a finite number of dynamic forms."33 If—a big if—we can track the loci of these strange attractors, we might be able to find the right sort of trigger for a hurricane, and if we then deploy it at the right moment, we might be able to turn storms away from where we don't want them to where they would do the least harm. Or, if we are not careful and the right moment turns out to be the wrong moment, to where they would do more harm than ever. Now there's an insurance company's nightmare.
Another idea bruited about was to coat the ocean beneath an embryo storm with biodegradable oil, to separate the disturbance from its fuel, the warm water of tropical oceans. The idea seems fine, but the problems are enormous—somewhat akin to the big bad wolf huffing and puffing at a fortress instead of a hut. Where to find enough oil, especially biodegradable oil, to spread over so vast an area? How to get enough vessels to the right place at the right time to do the spreading? How, indeed, to know which embryo disturbance was going to turn into a hurricane in the first place? And afterward, provided it worked, what to do about the wild creatures, the whales and the dolphins and the sea birds, affected by the oil?
On Hoffman's computer, a change in wind speeds of a mere 5 miles an hour was enough to steer a storm past an island instead of over it; and something as apparently small as a one-degree change in temperature at the initial stage killed a simulated storm completely.34 But to change a thousand-square-mile piece of the atmosphere by one whole degree would take a massive amount of energy, almost as much as was latent in the storm itself. Where would this energy come from? Will satellites eventually beam down enough heat to change atmospheric temperatures? What unforeseen consequences will that have on weather and climate? Most ecolo-gists believe the whole notion of control is misguided, and that man's natural penchant for meddling with the environment can only make things worse.
And there is one more difficulty with translating computer models into reality. Scientists can do hundreds of runs in the simulation models to find the one small tweaking that would cause just the right result. It can't be done by trial and error in the real world, because there is no way of telling ahead of time what consequence any single small change will have. The chances of making things worse are equally as good as making them better.
Despite all this, one fairly simple-to-execute method does exist to kill budding hurricanes while still tropical storms. If a massive explosion were to take place beneath the ocean, driving cool water from the deep to the surface, it would deprive the storm of its fuel and would stop it in its tracks. But an explosion that large would pretty much have to be a nuclear fusion device, a hydrogen bomb, and it's hard to see such a thing being tolerated by any population keen on self-preservation—any such explosion would cause extensive radiation contamination, massive fish kills, and tsunamis, which collectively would do more damage than the hurricane itself. Much better to follow the ecologists' dictum, and do nothing. Put the money to living more prudently, construct stronger and more hurricane-proof buildings farther inland, and leave the shore to the wild winds and the sea birds.